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  • 1.
    Aggerstam, Thomas
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Andersson, T.G.
    Holmström, Petter
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Jänes, Peter
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Liu, X. Y.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Thylén, Lars
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    GaN/AlN multiple quantum well structures grown by MBE on GaN templates for 1.55 mu m intersubband absorption2007In: Quantum Sensing and Nanophotonic Devices IV / [ed] Razeghi, M; Brown, GJ, 2007, Vol. 6479, p. 64791E-1-64791E-12Conference paper (Refereed)
    Abstract [en]

    We have used MBE to grow MQW structures on MOVPE GaN/sapphire templates. The MQW devices are intended for high speed intersubband electroabsorption modulator devices operating at 1.55-mu m. The GaN/AlN multiple quantum well material was systematically studied regarding the surface morphology, structural characterization and optical property by atomic force microscopy, X-ray diffraction and Fourier transform infrared spectroscopy, respectively. The intersubband resonance energy was also calculated considering many-body effects in n-type doped structures. The multiple quantum well structure showed superior performance in terms of linewidth when grown on GaN templates as compared on sapphire. GaN quantum well and AlN barriers with a thickness of 3.3 and 4.2 nm respectively resulted in FWHM of the intersubband absorption peak as low as 93 meV at an absorption energy of 700 meV. This is promising for intersubband modulator applications.

  • 2.
    Aggerstam, Thomas
    et al.
    KTH, School of Information and Communication Technology (ICT), Centres, Electrum Laboratory, ELAB.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Centres, Electrum Laboratory, ELAB.
    Radamson, Henry H.
    KTH, School of Information and Communication Technology (ICT), Centres, Electrum Laboratory, ELAB.
    Sjödin, Mikael
    KTH, School of Information and Communication Technology (ICT), Centres, Electrum Laboratory, ELAB.
    Lorenzini, P.
    CNRS-CHREA.
    Look, D.C.
    Semiconductor Research Center, Wright State University.
    Investigation of the interface properties of MOVPE grown AlGaN/GaN high electron mobility transistor (HEMT) structures on sapphire2006In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 515, no 2, p. 705-707Article in journal (Refereed)
    Abstract [en]

    We have developed a virtual GaN substrate on sapphire based on a two-step growth method. By optimizing the growth scheme for the virtual substrate we have improved crystal quality and reduced interface roughness. Our Al0.22Ga0.78N/GaN HEMT structure grown on the optimized semi-insulating GaN virtual substrate, exhibits Hall mobilities as high as 1720 and 7350 cm(2)/Vs and sheet carrier concentrations of 8.4 x 1012 and 10.0 x 1012 cm(-2) at 300 K and 20 K, respectively The presence of good AlGaN/GaN interface quality and surface morphology is also substantiated by X-Ray reflectivity and Atomic Force Microscopy measurements. A simplified transport model is used to fit the experimental Hall mobility.

  • 3.
    Aggerstam, Thomas
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Pinos, Andrea
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Marcinkevicius, Saulius
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Optics.
    Linnarsson, Margareta
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Electron and hole capture cross-sections of Fe acceptors in GaN:Fe epitaxially grown on sapphire2007In: Journal of Electronic Materials, ISSN 0361-5235, E-ISSN 1543-186X, Vol. 36, no 12, p. 1621-1624Article in journal (Refereed)
    Abstract [en]

    Carrier trapping of Fe (3+)/Fe2+ deep acceptors in epitaxially grown GaN:Fe on sapphire was studied by time-resolved photoluminescence. For the investigated Fe doping levels on the order of 10(18) cm(-3), the luminescence decay times are strongly dependent on the Fe concentration, indicating that Fe centers act as predominant nonradiative recombination channels. Linear dependence of the decay time on the iron concentration allows estimation of the electron capture cross-section for the Fe3+ ions, which is equal to 1.9 x 10(-15) cm(2). The upper bound for the cross-section of the hole capture of Fe2+ was evaluated as 10 x 10(-15) cm

  • 4.
    Aggerstam, Thomas
    et al.
    KTH, School of Information and Communication Technology (ICT), Centres, Electrum Laboratory, ELAB.
    Sjödin, Mikael
    KTH, School of Information and Communication Technology (ICT), Centres, Electrum Laboratory, ELAB.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Centres, Electrum Laboratory, ELAB.
    AlGaN/GaN high-electron-mobility transistors on sapphire with Fe-doped GaN buffer layer by MOVPE2006In: Physica Status Solidi C - Current Topics in Solid State Physics: Vol 3, No 6 / [ed] Hildebrandt S; Stutzmann M, 2006, Vol. 3, p. 2373-2376Conference paper (Refereed)
    Abstract [en]

    A simple AlGaN/GaN HEMT structure without any interlayer on Fe-doped GaN (GaN:Fe) grown by LP-MOVPE in one single run on sapphire is demonstrated. The surface segregation of Fe in GaN occurring during growth is identified. Hall measurements yield 2DEG (two dimensional electron gas) mobilities of 1700 and 10700 cm2/Vs and sheet carrier concentrations of 5.1×10 12 and 5.7×1012 cm-2 at 300 K and 20 K, respectively. Good pinch-off current-voltage (ID-VD) characteristics is observed from AlGaN/GaN HEMTs. A maximum drain current density of 0.6 A/mm and a peak extrinsic transconductance of 200 mS/mm have been observed. The HEMT structure yields very good device isolation as indicated by an isolation current of ≀1 nA at 20 V.

  • 5.
    Akram, Nadeem
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Kjebon, Olle
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Chacinski, Marek
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Berggren, Jesper
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Olsson, Fredrik
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Berrier, Audrey
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Experimental characterization of high-speed 1.55 mu m buried heterostructure InGaAsP/InGaAlAs quantum-well lasers2009In: Journal of the Optical Society of America. B, Optical physics, ISSN 0740-3224, E-ISSN 1520-8540, Vol. 26, no 2, p. 318-327Article in journal (Refereed)
    Abstract [en]

    Detailed experimental characterization is performed for 1550 nm semi-insulating regrown buried heterostructure Fabry-Perot (FP) lasers having 20 InGaAsP/InGaAlAs strain-balanced quantum wells (QWs) in the active region. Light-current-voltage performance, electrical impedance, small-signal response below and above threshold, amplified spontaneous emission spectrum below threshold and relative intensity noise spectrum are measured. Different laser parameters such as external differential quantum efficiency eta(d), background optical loss alpha(i), K-factor, D-factor, characteristic temperature T-0, differential gain dg/dn, gain-compression factor epsilon, carrier density versus current, differential carrier lifetime tau(d), optical gain spectrum below threshold, and chirp parameter alpha are extracted from these measurements. The FP lasers exhibited a high T-0 (78-86.5 degrees C) and very high-resonance frequency (23.7 GHz). The results indicate that appropriately designed lasers having a large number of InGaAsP well/InGaAlAs barrier QWs with shallow valence-band discontinuity can be useful for un-cooled high-speed direct-modulated laser applications.

  • 6.
    Akram, Nadeem
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Kjebon, Olle
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Chacinski, Marek
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Berggren, Jesper
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Olsson, Fredrik
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Berrier, Audrey
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    High-Speed Performance of 1.55 µm Buried Hetero-Structure Lasers with 20 InGaAsP/InGaAlAs Quantum-Wells2006In: 2006 European Conference on Optical Communications Proceedings, ECOC 2006, IEEE , 2006, p. 1-2Conference paper (Refereed)
    Abstract [en]

    1550 nm re-grown FP lasers having 20 InGaAsP/InGaAlAs strain-balanced QWs exhibit low threshold current density, high T0 (78.0 #x000B0;C) and high resonance frequency (24 GHz) indicating that a large number of shallow barrier QWs are attractive for un-cooled high-speed direct-modulation applications.

  • 7.
    Akram, Nadeem
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Kjebon, Olle
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Marcinkevičius, Saulius
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Berggren, Jesper
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Olsson, Fredrik
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    The effect of barrier composition on the vertical carrier transport and lasing properties of 1.55-mu m multiple quantum-well structures2006In: IEEE Journal of Quantum Electronics, ISSN 0018-9197, E-ISSN 1558-1713, Vol. 42, no 7, p. 713-714Article in journal (Refereed)
    Abstract [en]

    In this paper, the effect of barrier bandgap and composition on the optical performance of 1.55-mu m InGaAsP/In-GaAsP and InGaAsP/InGaAlAs multiple quantum-well structures and Fabry-Perot lasers is evaluated experimentally. Direct vertical carrier transport measurements were performed through strain-compensated multiple quantum-well (MQW) test structures using femto-second laser pulse excitation and time-resolved photoluminescence up-conversion method. MQW test structures were grown with different barrier composition (InGaAsP and InGaAlAs) and barrier bandgap (varied from lambda(g) = 1440 to 1260 nm) having different conduction band Delta E-c and valence band discontinuity Delta E-v, while keeping the same InGaAsP well composition for all the structures. The ambipolar carrier transport was found to be faster in the structures with lower valence band discontinuity Delta E-v. Regrown semi-insulating buried heterostructure Fabry-Perot (SIBH-FP) lasers were fabricated from similar QWs and their static light-current-voltage characteristics (including optical gain and chirp spectra below threshold) and thermal characteristics were measured. Lasers with InGaAlAs barrier showed improved high-temperature operation, higher optical gain, higher differential gain, and lower chirp, making them suitable candidates for high-bandwidth directly modulated uncooled laser applications.

  • 8. Andersson, T. G.
    et al.
    Liu, X. Y.
    Aggerstam, Thomas
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Holmström, Petter
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Thylen, Lars
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Chen, Y. L.
    Hsieh, C. H.
    Lo, I.
    Macroscopic defects in GaN/AlN multiple quantum well structures grown by MBE on GaN templates2009In: Microelectronics Journal, ISSN 0026-2692, Vol. 40, no 2, p. 360-362Article in journal (Refereed)
    Abstract [en]

    We have used MBE to grow in AlN/GaN superlattices, with different number of periods, on 2.5-mu m-thick MOVPE-GaN templates to study the development of defects such as surface deformation due to strain. After growth the samples were studied by atomic force microscopy (AFM), transmission electron microscopy (TEM), XRD and Fourier transform infrared spectroscopy (FT-IR). The strain increased with the number of quantum wells (QWs) and eventually caused defects such as microcracks visible by optical microscopy at four or more QW periods. High-resolution TEM images showed shallow recessions on the surface (surface deformation) indicating formation of microcracks in the MQW region. The measured intersubband (IS) absorption linewidth from a four period structure was 97 meV, which is comparable with the spectrum from a 10 period structure at an absorption energy of similar to 700 meV. This indicates that the interface quality of the MQW is not substantially affected by the presence of cracks.

  • 9.
    Angulo Barrios, C.
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT. KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Messmer, L. R.
    Holmgren, M.
    Lovqvist, A.
    Carlsson, C.
    Larsson, A.
    Halonen, J.
    Ghisoni, M.
    Stevens, Renaud
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    GaAs/AlGaAs buried-heterostructure laser diodes with semi-insulating GaInP:Fe regrowth2001In: Lasers and Electro-Optics, 2001. CLEO/Pacific Rim 2001. The 4th Pacific Rim Conference on, 2001, Vol. 2Conference paper (Refereed)
    Abstract [en]

    GaAs/AlGaAs buried-heterostructure in-plane lasers and vertical-cavity surface-emitting lasers using GaInP:Fe as the burying layer have been fabricated and investigated. Regrowth of GaInP:Fe around etched laser mesas was achieved by hydride vapor phase epitaxy. The lasers exhibit good performance under CW operation and show promising high-speed characteristics.

  • 10. Arulkumaran, S.
    et al.
    Ng, G. I.
    Tan, C. L.
    Liu, Z. H.
    Bu, J.
    Radhakrishnan, K.
    Aggerstam, T.
    Sjodin, M.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Enhancement of both direct-current and microwave characteristics of AlGaN/GaN high-electron-mobility transistors by furnace annealing2006In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 88, no 2Article in journal (Refereed)
    Abstract [en]

    The enhancement of both direct-current (dc) and microwave characteristics of AlGaN/GaN high-electron-mobility transistors (HEMTs) were demonstrated by conventional furnace annealing at 400 degrees C for 5 min. Due to the improvement in Ni/Au Schottky contact properties by furnace annealing, about 17%, 34%, 23%, and 25% of enhancements in maximum drain current density, maximum extrinsic transconductance (g(m max)), cutoff frequency and maximum oscillation frequency were observed, respectively. A positive threshold voltage shift and the increase in g(m max) can also be correlated to the improved Schottky parameters such as ideality factor and barrier height. The annealed devices exhibited low reverse gate-leakage-current by more than three orders of magnitude and low drain-leakage-current by two orders of magnitude. Correspondingly, the devices exhibited 55% of higher breakdown voltage after annealing. The furnace annealing is an effective and viable means to enhance both dc and microwave characteristics of AlGaN/GaN HEMTs.

  • 11. Azarov, A.Yu.
    et al.
    Hallén, Anders
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Jensen, J.
    Aggerstam, Thomas
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    High dose Fe implantation of gan: Damage build-up and dopant redistribution2008In: PROCEEDINGS OF THE 17TH INTERNATIONAL VACUUM CONGRESS/13TH INTERNATIONAL CONFERENCE ON SURFACE SCIENCE/INTERNATIONAL CONFERENCE ON NANOSCIENCE AND TECHNOLOGY, 2008, Vol. 100, no PART 4Conference paper (Refereed)
    Abstract [en]

    Undoped GaN epilayers implanted at room temperature with 50-325 keV Fe + ions in the fluence range of 1015 - 1017 ions/cm are studied by a combination of Rutherford backscattering/channeling spectrometry and time-of-flight elastic recoil detection analysis. Results show that for high ion fluences (>1 × 1016 cm-2) enhanced Fe concentration closer to the surface is observed. The Fe redistribution towards the surface increases as the ion fluence increases. Our findings are attributed to radiation enhanced diffusion during ion implantation and increasing of Fe diffusivity in the implantation-induced amorphous phase near the surface.

  • 12. Baek, J. H.
    et al.
    Soares, F. M.
    Seo, S. W.
    Jiang, W.
    Fontaine, N. K.
    Broeke, R. G.
    Cao, J.
    Olsson, Fredrik
    KTH, School of Information and Communication Technology (ICT), Material Physics (Closed 20120101), Semiconductor Materials, HMA (Closed 20120101).
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Material Physics (Closed 20120101), Semiconductor Materials, HMA (Closed 20120101).
    Yoo, S. J. B.
    10-GHz and 20-GHz channel spacing high-resolution AWGs on InP2009In: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 21, no 5, p. 298-300Article in journal (Refereed)
    Abstract [en]

    This letter reports on 10-GHz and 20-GHz channel-spacing arrayed waveguide gratings (AWGs) based on InP technology. The dimensions of the AWGs are 6.8 × 8.2 mm2 and 5.0 × 6.0 mm2, respectively, and the devices show crosstalk levels of 12 dB for the 10-GHz and 17 dB for the 20-GHz AWG without any compensation for the phase errors in the arrayed waveguides. The root-mean-square phase errors for the center arrayed waveguides were characterized by using an optical vector network analyzer, and are 18° for the 10-GHz AWG and 28° for the 10-GHz AWG.

  • 13. Barrios, C. A.
    et al.
    Lourdudoss, Sebastian
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Martinsson, H.
    Analysis of leakage current in GaAs/AlGaAs buried-heterostructure lasers with a semi-insulating GaInP: Fe burying layer2002In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 92, no 5, p. 2506-2517Article in journal (Refereed)
    Abstract [en]

    The leakage current in recently demonstrated GaAs/AlGaAs buried heterostructure (BH) lasers with a semi-insulating (SI) GaInP:Fe burying layer has been theoretically and experimentally analyzed. Calculated current-voltage characteristics of n-GaAs/SI-GaInP/n-GaAs and p-GaAs/SI-GaInP/p-GaAs planar configurations have been studied specially to assess the behavior of SI-GaInP:Fe under electron and hole injection. Two-dimensional potential profiles have been used to explain the leakage current mechanism in the SI-GaInP-buried lasers. Simulations reveal that the total leakage current decreases as the active trap concentration in the SI-GaInP:Fe burying layer is increased as expected, but the leakage current is strongly confined in the vicinity of the active region where the local leakage current density increases significantly as the trap density increases. It is found that the insertion of a n-GaInP hole blocking layer between the p-metal and the SI-GaInP layer decreases the total leakage current. Experimental light-current and current-voltage characteristics of fabricated lasers with and without an additional n-GaInP layer, and electroluminescence (EL) emitted from the burying GaInP:Fe layers corroborate qualitatively the simulations and demonstrate the benefits of using a n-GaInP layer for reducing leakage current in these type of lasers.

  • 14. Barrios, C. A.
    et al.
    Messmer, E. R.
    Holmgren, M.
    Lourdudoss, Sebastian
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    GaAs/AlGaAs buried heterostructure laser by wet etching and semi-insulating GaInP: Fe regrowth2000In: Electrochemical and solid-state letters, ISSN 1099-0062, E-ISSN 1944-8775, Vol. 3, no 9, p. 439-441Article in journal (Refereed)
    Abstract [en]

    Selective regrowth of semi-insulating Ga0.51In0.49P:Fe (SI-GaInP:Fe) by hydride vapor-phase epitaxy around Al-containing wet etched laser mesas is used for the first time to fabricate a GaAs/AlGaAs buried heterostructure laser emitting at 808 nm. The reverse and forward current-voltage characteristics measured at different temperatures up to 80 degrees C indicate no serious leakage current problems. The performance of the laser shows that the SI-GaInP: Fe burying layer fulfills its function as a current and optical confinement layer. The fabrication procedure and the laser characteristics are presented.

  • 15. Barrios, C. A.
    et al.
    Messmer, E. R.
    Holmgren, M.
    Risberg, A.
    Halonen, J.
    Lourdudoss, Sebastian
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Epitaxially regrown GaAs/AlGaAs laser mesas with semi-insulating GaInP: Fe and GaAs : Fe2001In: Journal of Electronic Materials, ISSN 0361-5235, E-ISSN 1543-186X, Vol. 30, no 8, p. 987-991Article in journal (Refereed)
    Abstract [en]

    Selective regrowth of semi-insulating iron-doped Ga0.51In0.49P (SI-GaInP:Fe) and SI-GaAs:Fe around GaAs/AlGaAs mesas by hydride vapor phase epitaxy (HVPE) has been achieved. A HCl based in-situ cleaning procedure has been used to remove aluminum oxide from the etched walls of the mesas. Regrowth conducted without proper cleaning results in an irregular interface with voids. Regrowth morphology aspects are also presented. Our cleaning and regrowth methods have been used for fabricating GaAs/AlGaAs buried heterostructure in-plane lasers and vertical-cavity surface-emitting lasers.

  • 16. Barrios, C. A.
    et al.
    Messmer, E. R.
    Risberg, A.
    Carlsson, C.
    Halonen, J.
    Ghisoni, M.
    Larsson, A.
    Lourdudoss, Sebastian
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    GaAs/AlGaAs buried-heterostructure vertical-cavity surface-emitting laser with semi-insulating GalnP: Fe regrowth2000In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 36, no 18, p. 1542-1544Article in journal (Refereed)
    Abstract [en]

    The authors report the first results of a GaAs/AlGaAs buried-heterostructure vertical-cavity surface-emitting laser (VCSEL) with semi-insulating Ga0.51In0.49P:Fe (SI-GaInP:Fe) as the burying layer. Regrowth of SI-GaInP:Fe around 15 mu m diameter and 8 mu m tall VCSEL mesas was carried out by hydride vapour phase epitaxy (HVPE). Under room temperature continuous wave (CW) operation. the device exhibited a threshold current of 3.5mA, a differential quantum efficency of 33% and a light output power of 4.2mW. CW operation at temperatures up to 97 degrees C is also demonstrated.

  • 17. Brocke, R. G.
    et al.
    Cao, J.
    Fontaine, N. K.
    Ji, C.
    Chubun, N.
    Olsson, Fredrik
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Kolner, B. H.
    Heritage, J. P.
    Yoo, S. J. B.
    Phase characterization of an InP based Optical-CDMA encoder using Frequency-Resolved Optical Gating (FROG)2005In: 2005 IEEE LEOS Annual Meeting Conference Proceedings (LEOS), 2005, p. 123-124Conference paper (Refereed)
    Abstract [en]

    We demonstrate the optical phase characterization of a monolithically integrated InP optical-CDMA encoder/decoder chip using frequency-resolved optical gating.

  • 18. Broeke, Ronald G.
    et al.
    Cao, Jin
    Ji, Chen
    Seo, Sang-Woo
    Du, Yixue
    Fontaine, Nick K.
    Baek, Jong-Hwa
    Yan, John
    Soares, Francisco M.
    Olsson, Fredrik
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Pham, Anh-Vu H.
    Sheam, Michael
    Scherer, Axel
    Yoo, S. J. Ben
    Optical-CDMA in InP2007In: IEEE Journal of Selected Topics in Quantum Electronics, ISSN 1077-260X, E-ISSN 1558-4542, Vol. 13, no 5, p. 1497-1507Article in journal (Refereed)
    Abstract [en]

    This paper describes the InP platforms for photonic integration and the development on these platforms of an optical code division multiple access (O-CDMA) system for local area networks. We demonstrate three building blocks of this system: an optical pulse source, an encoder/decoder pair, and a threshold detector. The optical pulse source consists of an integrated colliding pulse-mode laser with nearly transform-limited 10 Gb/s pulses and optical injection locking to an external clock for synchronization. The encoder/decoder pair is based on arrayed waveguide gratings. Bit-error-rate measurements involving six users at 10 Gb/s showed error-free transmission, while O-CDMA codes were calibrated using frequency resolved optical gating. For threshold detection after the decoder, we compared two Mach-Zehnder interferometer (MZI)-based optical thresholding schemes and present results on a new type of electroabsorber-based MZI.

  • 19. Cao, J.
    et al.
    Broeke, R. G.
    Fontaine, N.
    Cong, W.
    Ji, C.
    Du, Y.
    Chubun, N.
    Aihara, K.
    Pham, A. -V
    Heritage, J. P.
    Kolner, B. H.
    Yoo, S. J. B.
    Olsson, F.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Stephan, P. L.
    Error-free spectral encoding and decoding operation of InP O-CDMA encoder2006In: 2006 Optical Fiber Communication Conference, and the 2006 National Fiber Optic Engineers Conference, 2006Conference paper (Refereed)
    Abstract [en]

    We report error-free spectral encoding and decoding operation of an InP monolithic, ultra-compact optical-CDMA encoder/decoder photonic chip pair. The experimental results demonstrate the strong potential for realizing high performance O-CDMA networks with InP micro-systems.

  • 20. Cao, J.
    et al.
    Broeke, R. G.
    Ji, C.
    Du, Y.
    Chubun, N.
    Bjeletich, P.
    Tekin, T.
    Stephan, P. L.
    Olsson, F
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Yoo, S. J. B.
    Spectral encoding and decoding of monolithic InP OCDMA encoder2005In: 31st European Conference on Optical Communications (ECOC 2005), 2005, Institution of Engineering and Technology, 2005, Vol. 2005, no CP502, p. 501-502Conference paper (Refereed)
    Abstract [en]

    We report the optical-coding operation of monolithic, ultra-compact optical-CDMA encoder and decoder pair, consisting of InP based integrated AWGs and phase modulators. The encoder and decoder successfully demonstrate eight-bit Walsh code based encoding and decoding.

  • 21. Cao, J.
    et al.
    Broeke, R. G.
    Ji, C.
    Du, Y.
    Chubun, N.
    Bjeletich, P.
    Yoo, S. J. B.
    Olsson, Fredrik
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Stephan, P. L.
    A monolithic ultra-compact inp o-cdma encoder with: Planarization by hvpe regrowth2006In: OFC/NFOEC, Optical Society of America, 2006Conference paper (Refereed)
    Abstract [en]

    We report a monolithic, ultra-compact optical-CDMA encoder/decoder photonic chip in InP with surface planarization by low-pressure Hydride-Vapor-Phase-Epitaxy regrowth. The chip consists of an AWG pair and eight electro-optic phase shifters and demonstrated excellent encoding operation.

  • 22. Cao, J.
    et al.
    Broeke, R. G.
    Ji, C.
    Du, Y.
    Chubun, N.
    Bjeletich, P.
    Yoo, S. J. B.
    Olsson, Fredrik
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Stephan, P. L.
    A monolithic ultra-compact inp o-cdma encoder with: Planarization by hvpe regrowth2005In: Optics InfoBase Conference Papers, Optics Info Base, Optical Society of America, 2005Conference paper (Refereed)
    Abstract [en]

    We report a monolithic, ultra-compact optical-CDMA encoder/decoder photonic chip in InP with surface planarization by low-pressure Hydride-Vapor-Phase-Epitaxy regrowth. The chip consists of an AWG pair and eight electro-optic phase shifters and demonstrated excellent encoding operation.

  • 23.
    Cao, Jing
    et al.
    Department of Electrical and Computer Engineering, University of California.
    Broeke, R. G.
    Department of Electrical and Computer Engineering, University of California.
    Fontaine, N. K.
    Department of Electrical and Computer Engineering, University of California.
    Ji, C.
    Department of Electrical and Computer Engineering, University of California.
    Du, Y.
    Department of Electrical and Computer Engineering, University of California.
    Chubun, N.
    Department of Electrical and Computer Engineering, University of California.
    Aihara, K.
    Department of Electrical and Computer Engineering, University of California.
    Pham, Anh-Wu
    Department of Electrical and Computer Engineering, University of California.
    Olsson, Fredrik
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Yoo, S. J. Ben
    Department of Electrical and Computer Engineering, University of California.
    Demonstration of Spectral Phase O-CDMA Encoding and Decoding in Monolithically Integrated Arrayed-Waveguide-Grating-Based Encoder2006In: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 18, no 21-24, p. 2602-2604Article in journal (Refereed)
    Abstract [en]

    We report on successful spectral phase encoding and decoding operation in a pair of monolithically integrated InP encoder chips, each consisting of an arrayed waveguide grating (AWG) pair and an eight-channel electrooptic phase shifter array. The monolithic fabrication process includes anisotropic reactive ion etching and planarizing hydride-vapor-phase-epitaxy lateral regrowth to realize buried hetero-waveguide structures in AWGs and phase shifters. Electrooptical modulation in the phase shifter arrays in the encoder chip achieved Walsh-code-based optical code-division multiple access (O-CDMA) encoding and decoding. The matched-code encoding-decoding operation resulted in error-free performance in the presence of an interferer, indicating good potential for O-CDMA network applications.

  • 24. Carlsson, C.
    et al.
    Barrios, C. A.
    Messmer, E. R.
    Lovqvist, A.
    Halonen, J.
    Vukusic, J.
    Ghisoni, M.
    Lourdudoss, Sebastian
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Larsson, A.
    Performance characteristics of buried heterostructure VCSELs using semi-insulating GaInP: Fe regrowth2001In: IEEE Journal of Quantum Electronics, ISSN 0018-9197, E-ISSN 1558-1713, Vol. 37, no 7, p. 945-950Article in journal (Refereed)
    Abstract [en]

    We have fabricated GaAs-AlGaAs buried heterostructure vertical cavity surface emitting lasers, emitting at 850 nm, using semi-insulating GaInP:Fe regrowth and investigated their static properties. Lasers of different size (10-21 mum) have threshold currents in the range 2.8-7.0 mA, and produce a maximum output power of 1.7-6.0 mW at room temperature. The variation of threshold current with device size shows that the leakage current at the regrowth interface accounts for a significant part of the injection current. In spite of this, a differential quantum efficiency in the range 20%-30% is obtained which indicates that the regrowth interface is smooth and does not introduce any significant scattering loss. Studies of the transverse mode properties suggest that the GaInP provides weak guiding, resulting in single mode operation up to an output power of 0.7 mW and a beam divergence of only 6 degrees for lasers as large as 10 mum.

  • 25. Cheung, S. T. S.
    et al.
    Soares, F. M.
    Baek, J. H.
    Guan, B.
    Olsson, Fredrik
    KTH, School of Information and Communication Technology (ICT), Material Physics (Closed 20120101), Semiconductor Materials, HMA (Closed 20120101).
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Material Physics (Closed 20120101), Semiconductor Materials, HMA (Closed 20120101).
    Yoo, S. J. B.
    Monolithically integrated 10-GHz ring colliding pulse mode-locked laser for on-chip coherent communications2012In: 2012 Conference on Lasers and Electro-Optics, CLEO 2012, 2012, p. 6326206-Conference paper (Refereed)
    Abstract [en]

    We report a 10-GHz ring resonator colliding pulse mode-locked (CPM) laser with tunable couplers for InP-based monolithically integrated optical coherent communication system applications. Optimization included adjusting the saturable absorber reverse bias, driving RF-frequency, and amplifier gain current. Hybrid mode-locking (HML) resulted in a minimal pulse width of 10.1ps for 6 nm spectral width.

  • 26. Darakchieva, V.
    et al.
    Monemar, B.
    Paskova, T.
    Einfeldt, S.
    Hommel, D.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT).
    Phonons in strained AlGaN/GaN superlattices2007In: Physica Status Solidi. C, Current topics in solid state physics, ISSN 1610-1634, E-ISSN 1610-1642, Vol. 4, no 1, p. 170-174Article in journal (Refereed)
    Abstract [en]

    Phonons in strained AlGaN/GaN superlattices (SLs) with constant periods but different Al composition have been studied using a combination of infrared spectroscopic ellipsometry and Raman scattering spectroscopy. The following SL modes were identified: i) AlGaN localized E1(TO) modes identified for the first time and AlGaN localized A1 (LO) phonons; ii) GaN localized E2, E1(TO) and A1(LO) phonons; iii) delocalized E1(LO) phonons; iv) A1(TO) phonon; v) two modes around 660 cm-1 and 594-625 cm-1, respectively, not predicted by theory. The effects of strain and composition on the phonon frequencies were established and discussed.

  • 27. Douheret, O.
    et al.
    Anand, Srinivasan
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Barrios, C. A.
    Lourdudoss, Sebastian
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Characterization of GaAs/AlGaAs laser mesas regrown with semi-insulating GaInP by scanning capacitance microscopy2002In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 81, no 6, p. 960-962Article in journal (Refereed)
    Abstract [en]

    In this work, cross-sectional scanning capacitance microscopy (SCM) is used to investigate GaAs/AlGaAs buried heterostructure lasers. Laser mesas are buried with GaInP:Fe selectively regrown by hydride vapor phase epitaxy. It is shown that a complete 2D map of the electrical properties of device structure including, delineation of regrown interfaces and electrical nature of the regrown GaInP layer can be obtained. The behavior of the SCM signal with ac bias is used to verify the semi-insulating nature of the regrown layer at different locations of the sample. The measured SCM signal for the regrown GaInP:Fe layer is uniformly zero, indicating very low free carrier densities and confirming semi-insulating properties. This observation strongly suggests, in addition, uniform Fe incorporation in the regrown layers, close to and far away from the mesa. Finally, a nanoscale feature in the SCM contrast appearing as a bright (dark) spot in dC/dV mode (feedback bias mode) is observed at the mesa sidewall close to the interface between the regrown GaInP:Fe and the p-cladding layer. The origin of this contrast is discussed in terms of local band-bending effects and supported by 2D Poisson simulations of the device structure.

  • 28. Estephan, Elias
    et al.
    Saab, Marie-belle
    Larroque, Christian
    Martin, Marta
    Olsson, Fredrik
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Gergely, Csilla
    Peptides for functionalization of InP semiconductors2009In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 337, no 2, p. 358-363Article in journal (Refereed)
    Abstract [en]

    The challenge is to achieve high specificity in molecular sensing by proper functionalization of micro/nano-structured semiconductors by peptides that reveal specific recognition for these structures. Here we report on surface modification of the InP semiconductors by adhesion peptides produced by the phage display technique. An M13 bacteriophage library has been used to screen 10(10) different peptides against the InP(0 0 1) and the InP(1 1 1) surfaces to finally isolate specific peptides for each orientation of the InP. MALDI-TOF/TOF mass spectrometry has been employed to study real affinity of the peptide towards the InP surfaces. The peptides serve for controlled placement of biotin onto InP to bind then streptavidin. Our Atomic Force Microscopy study revealed a total surface coverage of molecules when the InP surface was functionalized by its specific biotinylated peptide (YAIKGPSHFRPS). Finally, fluorescence microscopy has been employed to demonstrate the preferential attachment of the peptide onto a micro-patterned InP surface. Use of substrate specific peptides could present an alternative solution for the problems encountered in the actually existing sensing methods and molecular self-assembly due to the unwanted unspecific interactions.

  • 29. Fontaine, N. K.
    et al.
    Baek, J. -H
    Ji, C.
    Broeke, R. G.
    Zhou, X.
    Seo, S. -W
    Soares, F. M.
    Shearn, M.
    Scherer, A.
    Olsson, Fredrik E.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Liu, K. Y.
    Tsang, W. T.
    Yoo, S. J. B.
    Monolithically integratable colliding pulse modelocked laser source for O-CDMA photonic chip development2008Conference paper (Refereed)
    Abstract [en]

    We demonstrate modelocking of a colliding-pulse mode-locked laser formed by 3-μm-deep etched-mirrors on an InP platform for integration with passive waveguide components. Timing jitter of 243 fs and pulse width of 10 ps were measured.

  • 30. Fontaine, N. K.
    et al.
    Wei, J.
    Soares, F. M.
    Broeke, R. G.
    Seo, S. -W
    Baek, J. -H
    Cao, J.
    Okamoto, K.
    Yoo, S. J. B.
    Olsson, Fredrik
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Determination of 20 GHz InP AWG phase errors by measurement of AWG pulse train2007In: 2007 IEEE LEOS Annual Meeting Conference Proceedings, IEEE , 2007, p. 725-726Conference paper (Refereed)
    Abstract [en]

    The phase errors of a 20 GHz AWG fabricated on InP are determined by measuring the intensity and phase of the pulse train produced by the transmission of a short pulse through an AWG.

  • 31. Gaarder, A.
    et al.
    Marcinkevicius, Saulius
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Barrios, C. A.
    Lourdudoss, Sebastian
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Time-resolved micro-photoluminescence studies of deep level distribution in selectively regrown GaInP: Fe and GaAs : Fe2002In: Semiconductor Science and Technology, ISSN 0268-1242, E-ISSN 1361-6641, Vol. 17, no 2, p. 129-134Article in journal (Refereed)
    Abstract [en]

    We apply time-resolved photoluminescence with 1-2 mum spatial resolution for the characterization of deep centre distributions in semi-insulating GaInP:Fe and GaAs:Fe epitaxial layers regrown by hydride vapour phase epitaxy around etched GaAs mesas and GaAs/AlGaAs quantum well laser structures. In InGaP, Fe ions act as the main carrier recombination centres, while in Fe-doped GaAs both the Fe ions and As antisite defects have to be considered. The distribution of Fe ions in InGaP was found to be rather uniform and close to the target value. For GaAs:Fe, the number of ionized Fe and EL2 centres showed a certain increase at the mesa interfaces. In both cases, the high trap concentration was maintained throughout the regrown layers indicating good semi-insulating material properties.

  • 32. Gaarder, A.
    et al.
    Marcinkevicius, Saulius
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Barrios, C. A.
    Lourdudoss, Sebastian
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Time-resolved micro-photoluminescence studies of dopant distribution in selectively regrown GalnP: Fe around VCSELs2002In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T101, p. 89-91Article in journal (Refereed)
    Abstract [en]

    We apply time-resolved photoluminescence with 1.5 mum spatial resolution for characterization ofcarrier trap distribution in semi-insulating Ga0.51In0.49P:Fe layers regrown around GaAs/AlGaAs circular vertical cavity surface emitting laser mesas using hydride vapour phase epitaxy. The carrier trapping times are in the range from 10 to 15 ps and quite uniformly distributed throughout the burying GaInP:Fe layer, suggesting that the layer is semi-insulating everywhere. Simulations show that, in addition to the Fe dopants, the layer contains other, unintended carrier traps. The photoluminescence spectra reveal that the regrown GaInP:Fe material has several distinct regions with different band gaps. This is attributed to differences in the In/Ga composition and/or CuPt ordering of the GaInP.

  • 33. Gaarder, A.
    et al.
    Marcinkevicius, Saulius
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Messmer, E. R.
    Lourdudoss, Sebastian
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Dopant distribution in selectively regrown InP: Fe studied by time-resolved photoluminescence2001In: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 226, no 4, p. 451-457Article in journal (Refereed)
    Abstract [en]

    We apply time-resolved photoluminescence with 1 mum spatial resolution for the characterization of iron distribution in semi-insulating InP:Fe epitaxial layers regrown by hydride vapor-phase epitaxy around etched mesas. The InP:Fe regrowth was carried out on InP:S mesas etched both along the [110] and [110] crystallographic directions, as well as on InP/InGaAsP in-plane lasers. In all cases, the Fe concentration was found to be close to the target values and showed little variation along the regrown layers.

  • 34.
    Holmström, Petter
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Liu, X. Y.
    Uchida, H.
    Aggerstam, Thomas
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Kikuchi, A.
    Kishino, K.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Andersson, T.G.
    Thylén, Lars
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Intersubband photonic devices by group-III nitrides2007In: Optoelectronic Materials And Devices II / [ed] Nakano, Y, 2007, Vol. 6782, p. N7821-N7821Conference paper (Refereed)
    Abstract [en]

    The characteristics of intersubband transitions in III-nitride quantum wells are promising for detectors and all-optical switches through a high intrinsic speed (similar to 1 THz), and can also provide a high optical saturation power and a desired small negative chirp parameter in electroabsorption modulators. The high LO-phonon energy allows to improve the operating temperature of THz emitters. Recent achievements and prospects for intersubband III-nitride photonic devices, mainly for lambda=1.55 mu m, are briefly reviewed. Further, means to enhance material quality by achieving crack-free growth of GaN/AlN multiple-quantum-well (MQW) structures, and by employing intersubband transitions in multiple-quantum-disk (MQD) structures incorporated into dislocation free GaN nanocolumns are discussed. We investigate the occurrence of cracks in MBE-grown GaN/AlN MQWs on GaN MOVPE templates with respect to the buffer layer, the number of QWs and the temperature reduction rate after growth. Intersubband absorption in GaN/AlN MQDs in the wavelength range 1.38-1.72 mu m is demonstrated in three samples grown on Si(111).

  • 35. Jahan, D.
    et al.
    Soderstrom, D.
    Lourdudoss, Sebastian
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Kinetic study of InP: Fe growth by LP-HVPE with ferrocene as Fe source2000In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 147, no 2, p. 744-746Article in journal (Refereed)
    Abstract [en]

    A kinetic study of InP:Fe growth has been carried out in a low pressure hydride vapor phase epitaxy (LP-HVPE) reactor using Ferrocene as iron source. The influence of the ferrocene partial pressure on the growth behavior has been investigated. A drastic decrease of the growth rate in the presence of ferrocene has been experimentally measured. This effect is explained to be due to cyclopentadiene adsorption. A kinetic model, that takes into account this adsorption, is proposed, which explains the observed experimental results.

  • 36.
    Jaskorzynska, Bozena
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Centres, Kista Photonics Research Center, KPRC.
    Wosinski, Lech
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Centres, Kista Photonics Research Center, KPRC.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Centres, Kista Photonics Research Center, KPRC.
    Olsson, Fredrik
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Centres, Kista Photonics Research Center, KPRC.
    Active Si-based photonics via heterogeneous integration2008In: ICTON 2008: PROCEEDINGS OF 2008 10TH ANNIVERSARY INTERNATIONAL CONFERENCE ON TRANSPARENT OPTICAL NETWORKS, VOL 2 / [ed] Marciniak, M, NEW YORK: IEEE , 2008, p. 30-33Conference paper (Refereed)
    Abstract [en]

    We review major breakthroughs in realizing silicon-based active components by heterogeneous integration with III-V semiconductors, or nonlinear organic materials. In more detail we describe examples of our concepts and technological approach addressing this goal. This includes designs for widely tunable filters and new routes for heteroepitaxy and selective area growth of InP on silicon.

  • 37. Ji, C.
    et al.
    Broeke, R. G.
    Du, Y.
    Cao, J.
    Chubun, N.
    Bjeletich, P.
    Olsson, F.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Welty, R.
    Reinhardt, C.
    Stephan, P. L.
    Yoo, S. J. B.
    Monolithically integrated InP-based photonic chip development for O-CDMA systems2005In: IEEE Journal of Selected Topics in Quantum Electronics, ISSN 1077-260X, E-ISSN 1558-4542, Vol. 11, no 1, p. 66-77Article in journal (Refereed)
    Abstract [en]

    This paper discusses photonic integration efforts toward developing an InP-based inonolithically integrated photonic chip for optical code-division multiple-access (O-CDMA) system applications. The chip design includes the colliding pulsed mode (CPM) locked laser, the. Mach-Zehnder interferometer-based threshold detector (MZI), and the monolithic O-CDMA encoder/decoder chip based on array-waveguide-gratings and phase modulator arrays. The compact 4 x I cm monolithic chip can replace a complex and large O-CDMA setup based on bulk optics. The integration technique involves active-passive integration using dry etching, metal organic chemical vapor deposition growth, and lateral hydride vapor phase epitaxy regrowth technologies. The fabricated CPM showed stable 1.54 ps modelocked laser output, the MZI showed excellent O-CDMA threshold detection, and the O-CDMA encoder showed Walsh-code O-CDMA, encoding. Further, the fabricated devices showed excellent planarity, which accelerate our progress toward monolithic integration of O-CDMA systems.

  • 38. Jiang, W.
    et al.
    Fontaine, K.
    Soares, F. M.
    Baek, J. H.
    Okamoto, K.
    Yoo, J. B.
    Olsson, Fredrik
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Dynamic phase-error compensation for high-resolution InP arrayed-waveguide grating using electro-optic effect2008In: Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS, 2008, p. 53-54Conference paper (Refereed)
    Abstract [en]

    We demonstrate for the first time the phase-error compensation for a 20-GHz-spacing InP AWG with electrooptic phase shifters placed on 42 arrayed waveguides. The experiment results show successful phase control and 6-dB reduction of crosstalk.

  • 39. Jiang, W.
    et al.
    Okamoto, K.
    Soares, F. M.
    Olsson, Fredrik
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Yoo, S. J. B.
    5 GHz channel spacing InP-based 32-channel Arrayed-Waveguide Grating2009In: OFC: 2009 Conference on Optical Fiber Communication, IEEE , 2009, p. 2660-2662Conference paper (Refereed)
    Abstract [en]

    We realize a 32-channel InP-based Arrayed-Waveguide Grating (AWG) with a 5-GHz channel spacing. The AWG shows approximately 14 dB excess-loss, 9 dB crosstalk, and 21 × 22 mm2 dimensions.

  • 40. Jiang, W.
    et al.
    Soares, F. M.
    Seo, S. W.
    Baek, J. H.
    Fontaine, N. K.
    Broeke, R. G.
    Cao, J.
    Yan, J.
    Okamoto, K.
    Olsson, Fredrik E.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Pham, A.
    Yoo, S. J. B.
    A monolithic inp-based photonic integrated circuit for optical arbitrary waveform generation2008Conference paper (Refereed)
    Abstract [en]

    We demonstrate a compact monolithically-integrated InP optical arbitrary waveform generator, consisting of an arrayed waveguide grating pair with 10 GHz channel spacing, 10 high-speed optical amplitude modulators, and 10 high-speed optical phase modulators.

  • 41.
    Junesand, Carl
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Gau, Ming-Horn
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Sun, Yanting
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Lo, Ikal
    Jimenez, Juan
    Aitor Postigo, Pablo
    Miguel Morales, Fransisco
    Hernandez, Jesus
    Molina, Sergio
    Abdessamad, Aouni
    Pozina, Galia
    Hultman, Lars
    Pirouz, Pirouz
    Defect reduction in heteroepitaxial InP on Si by epitaxial lateral overgrowth2014In: Materials Express, ISSN 2158-5849, Vol. 4, no 1, p. 41-53Article in journal (Refereed)
    Abstract [en]

    Epitaxial lateral overgrowth of InP has been grown by hydride vapor phase epitaxy on Si substrates with a thin seed layer of InP masked with SiO2. Openings in the form of multiple parallel lines as well as mesh patterns from which growth occurred were etched in the SiO2 mask and the effect of different growth conditions in terms of V/III ratio and growth temperature on defects such as threading dislocations and stacking faults in the grown layers was investigated. The samples were characterized by cathodoluminescence and by transmission electron microscopy. The results show that the cause for threading dislocations present in the overgrown layers is the formation of new dislocations, attributed to coalescence of merging growth fronts, possibly accompanied by the propagation of pre-existing dislocations through the mask openings. Stacking faults were also pre-existing in the seed layer and propagated to some extent, but the most important reason for stacking faults in the overgrown layers was concluded to be formation of new faults early during growth. The formation mechanism could not be unambiguously determined, but of several mechanisms considered, incorrect deposition due to distorted bonds along overgrowth island edges was found to be in best agreement with observations.

  • 42.
    Junesand, Carl
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Hu, Chen
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Wang, Zhechao
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Metaferia, Wondwosen
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Dagur, Pritesh
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Pozina, Galia
    Hultman, Lars
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Effect of the Surface Morphology of Seed and Mask Layers on InP Grown on Si by Epitaxial Lateral Overgrowth2012In: Journal of Electronic Materials, ISSN 0361-5235, E-ISSN 1543-186X, Vol. 41, no 9, p. 2345-2349Article in journal (Refereed)
    Abstract [en]

    Heteroepitaxy of InP on Si by epitaxial lateral overgrowth (ELOG) using a thin seed layer of InP as starting material is investigated, with special attention given to the effect of the surface morphology of the seed and the mask layers on the quality of the ELOG layers. Chemical mechanical polishing (CMP) has been used to improve the morphological and optical quality of InP grown by hydride vapor-phase epitaxy (HVPE) using ELOG. Two approaches have been investigated: polishing the InP seed layer on Si before depositing the SiO2 mask and polishing the SiO2 mask after its deposition on the unprocessed seed layer. For polishing the InP (seed)/Si, a two-step process with an aluminum oxide- and sodium hypochlorite-containing slurry as well as a slurry based on sodium hypochlorite mixed with citric acid was used. For SiO2 mask polishing, a slurry with colloidal silica as an abrasive was employed. In both cases, the SiO2 mask was patterned with double line openings and ELOG carried out in an HVPE reactor. Morphology and crystal quality of the resulting ELOG layers were studied with atomic force microscopy (AFM) and room-temperature panchromatic cathodoluminescence (PC-CL) in situ in a scanning electron microscope (SEM), respectively. The results show that, whereas both polishing approaches result in an ELOG InP layer with good morphology, its surface roughness is lower when the InP (seed)/Si is subjected to CMP prior to deposition of the SiO2 mask, than when only the SiO2 mask is polished. This approach also leads to a decrease in the number of defects generated during coalescence of the ELOG layers.

  • 43.
    Junesand, Carl
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics (Closed 20120101), Semiconductor Materials, HMA (Closed 20120101).
    Hu, Chen
    KTH, School of Information and Communication Technology (ICT), Material Physics (Closed 20120101), Semiconductor Materials, HMA (Closed 20120101).
    Wang, Zhechao
    KTH, School of Information and Communication Technology (ICT), Material Physics (Closed 20120101), Semiconductor Materials, HMA (Closed 20120101).
    Metaferia, Wondwosen
    KTH, School of Information and Communication Technology (ICT), Material Physics (Closed 20120101), Semiconductor Materials, HMA (Closed 20120101).
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Material Physics (Closed 20120101), Semiconductor Materials, HMA (Closed 20120101).
    Optimisation of seed and mask surfaces in epitaxial lateral overgrowth of indium phosphide on silicon for silicon photonics2011In: Conference Proceedings: International Conference on Indium Phosphide and Related Materials, VDE VERLAG GMBH , 2011, p. 1-4Conference paper (Refereed)
    Abstract [en]

    The effect of chemical mechanical polishing (CMP) on epitaxial lateral overgrowth (ELOG) of InP is investigated. To this end, silicon wafers with a seed layer of InP has been treated in two ways; by depositing SiO2 mask and polishing it prior to performing ELOG, and by growing additional InP directly on the InP/Si wafer and then polishing the InP layer prior to depositing and patterning SiO2 followed by subsequent ELOG. For InP seed, a two step process with Chemlox™ slurry and sodium hypochlorite mixed with citric acid-based slurry has been used whereas for SiO2 surface polishing, only one slurry was employed. Analysis of the ELOG layers has been carried out with atomic force microscope (AFM) and panchromatic cathodoluminescence (PC-CL) in-situ a scanning electron microscope (SEM). The results show that polishing the InP/Si layer has not only a beneficial effect on surface morphology of the ELOG layer but also on reduction of its defect density as a consequence of improved conditions for near-ideal coalescence.

  • 44.
    Junesand, Carl
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Kataria, Himanshu
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Metaferia, Wondwosen
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Julian, Nick
    Wang, Zhechao
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA. Ghent University, Dept. of Information Technology, Sint-Pietersnieuwstraat 41, 9000 Ghent, Belgium .
    Sun, Yan-Ting
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Bowers, John
    Pozina, Galia
    Hultman, Lars
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Study of planar defect filtering in InP grown on Si by epitaxial lateral overgrowth2013In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 3, no 11, p. 1960-1973Article in journal (Refereed)
    Abstract [en]

    InP thin films have been grown on InP/Si substrate by epitaxial lateral overgrowth (ELOG). The nature, origin and filtering of extended defects in ELOG layers grown from single and double openings in SiO2 mask have been investigated. Whereas ELOG layers grown from double openings occasionally exhibit threading dislocations (TDs) at certain points of coalescence, TDs are completely absent in ELOG from single openings. Furthermore, stacking faults (SFs) observed in ELOG layers grown from both opening types originate not from coalescence, but possibly from formation during early stages of ELOG or simply propagate from the seed layer through the mask openings. A model describing their propagation is devised and applied to the existent conditions, showing that SFs can effectively be filtered under certain conditions. ELOG layers grown from identical patterns on InP substrate contained no defects, indicating that the defect-forming mechanism is in any case not inherent to ELOG itself.

  • 45.
    Junesand, Carl
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Kataria, Himanshu
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Metaferia, Wondwosen
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Julian, Nick
    Wang, Zhechao
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Sun, Yanting
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Bowers, John
    Pozina, Galia
    Hultman, Lars
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Study of planar defect filtering in InP gwoun on Si by epitaxial lateral overgrowthManuscript (preprint) (Other academic)
  • 46.
    Junesand, Carl
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics (Closed 20120101), Semiconductor Materials, HMA (Closed 20120101).
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    ACTIVE PHOTONIC DEVICE2010Patent (Other (popular science, discussion, etc.))
  • 47.
    Junesand, Carl
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Metaferia, Wondwosen
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Olsson, Fredrik
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Avella, M.
    Jimenez, J.
    Pozina, G.
    Hultman, L.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Heteroepitaxial Growth of Indium Phosphide from Nano-openings Made by Masking on a Si(001) Wafer2010In: 2010 22ND INTERNATIONAL CONFERENCE ON INDIUM PHOSPHIDE AND RELATED MATERIALS (IPRM), 2010Conference paper (Refereed)
    Abstract [en]

    We investigate nano-eptiaxial lateral overgrowth (NELOG) of InP from the nano-sized openings on a seed layer on the silicon wafer, by Hydride Vapor Phase Epitaxy (HVPE). The grown layers were analyzed by cathodoluminescence (CL) in situ a scanning electron microscope (SEM) and transmission electron microscopy (TEM). The results from InP: S growth shows that the boundary plane of the grown layer has a major impact on the luminescence, indicating preferential orientation-dependent doping. Moreover, although there is clear evidence that most of the threading dislocations originating in the InP seed layer/Si interface are blocked by the mask, it appears that new dislocations are generated. Some of these dislocations are bounding planar defects such as stacking faults, possibly generated by unevenness in the mask. Finally, patterns where coalescence takes place at higher thickness seem to result in a rougher surface.

  • 48.
    Junesand, Carl
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Metaferia, Wondwosen
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Olsson, Fredrik
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Avella, M.
    Jimenez, J.
    Pozina, G.
    Hultman, L.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Heteroepitaxial Indium Phosphide on Silicon2010In: SILICON PHOTONICS AND PHOTONIC INTEGRATED CIRCUITS II, 2010, Vol. 7719Conference paper (Other academic)
    Abstract [en]

    There is an intense interest on integration of III-V materials on silicon and silicon-on-insulator for realisation of optical interconnects, optical networking, imaging and disposable photonics for medical applications. Advances in photonic materials, structures and technologies are the main ingredients of this pursuit. We investigate nano epitaxial lateral overgrowth (NELOG) of InP material from the nano openings on a seed layer on the silicon wafer, by hydride vapour phase epitaxy (HVPE). The grown layers were analysed by cathodoluminescence (CL) in situ a scanning electron microscope, time-resolved photoluminescence (TR-PL), and atomic force microscope (AFM). The quality of the layers depends on the growth parameters such as the V/III ratio, growth temperature, and layer thickness. CL measurements reveal that the dislocation density can be as low as 2 - 3.10(7) cm(-2) for a layer thickness of similar to 6 mu m. For comparison, the seed layer had a dislocation density of similar to 1.10(9) cm(-2). Since the dislocation density estimated on theoretical grounds from TRPL measurements is of the same order of magnitude both for NELOG InP on Si and on InP substrate, the dislocation generation appears to be process related or coalescence related. Pertinent issues for improving the quality of the grown InP on silicon are avoiding damage in the openings due to plasma etching, pattern design to facilitate coalescence with minimum defects and choice of mask material compatible with InP to reduce thermal mismatch.

  • 49.
    Junesand, Carl
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Olsson, Fredrik
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Xiang, Yu
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Gau, Ming-Horng
    KTH, School of Information and Communication Technology (ICT).
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Heterogeneous integration of indium phosphide on silicon by nano-epitaxial lateral overgrowth2009In: 2009 IEEE 21ST INTERNATIONAL CONFERENCE ON INDIUM PHOSPHIDE & RELATED MATERIALS (IPRM), 2009, p. 59-62Conference paper (Refereed)
    Abstract [en]

    InP on Si is grown by nano-epitaxial lateral overgrowth (nano-ELOG) on patterns consisting of net-type openings under different growth conditions. Analysis shows that net-type patterns yield large lateral growth rate and good optical quality. Different growth conditions have a substantial impact on growth rate and some effect on surface morphology, as well as on the optical quality. Optical quality is deemed to be affected partly by the amount of dislocations arising from the difference in thermal expansion coefficient between the mask and the InP layer, and partly by the layer thickness and surface morphology.

  • 50.
    Junesand, Carl
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Olsson, Fredrik
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Xiang, Yu
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Gau, Ming-Horng
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Surface morphology of indium phosphide grown on silicon by nano-epitaxial lateral overgrowth2009In: Physica Status Solidi. C, Current topics in solid state physics, ISSN 1610-1634, E-ISSN 1610-1642, Vol. 6, no 12, p. 2785-2788Article in journal (Refereed)
    Abstract [en]

    InP is grown on Si by nano-epitaxial lateral overgrowth (NELOG or nano-ELOG) on patterns consisting of net-type openings under different growth conditions. Surface morphology is characterized with AFM and profilometer and optical quality assessed by Micro Photoluminescence measurements (mu-PL). Results show that growth conditions affect both morphology and optical quality, with thicker layers generally corresponding to better surface morphology. Lower growth temperature seems to improve surface morphology irrespective of thickness, and ELOG layers exhibit significantly better morphology than the planar layer.

123 1 - 50 of 148
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