Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Scanning near-field microscopy of carrier lifetimes in m-plane InGaN quantum wells
KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.ORCID iD: 0000-0002-5007-6893
KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.ORCID iD: 0000-0002-4606-4865
KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
Show others and affiliations
2017 (English)In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 110, no 3, 031109Article in journal (Refereed) Published
Abstract [en]

Time-resolved scanning near-field photoluminescence (PL) spectroscopy was applied to map carrier lifetimes in wide m-plane InGaN/GaN quantum wells grown on on-axis and miscut substrates. Both radiative and nonradiative lifetimes were found to be spatially nonuniform. Lifetime variations were smaller for quantum wells grown on miscut, as compared to on-axis substrates. Correlation with surface topography showed that largest deviations of recombination times occur at +c planes of pyramidal hillocks of the on-axis sample. Observed correlation between radiative lifetimes and PL peak wavelength was assigned to a partial electron localization.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2017. Vol. 110, no 3, 031109
Keyword [en]
Photoluminescence spectroscopy, Surface topography, Electron localizations, InGaN quantum wells, InGaN/GaN quantum well, Largest deviation, Non-radiative lifetimes, Radiative lifetime, Scanning near field microscopy, Time-resolved scanning, Semiconductor quantum wells
National Category
Physical Sciences
Identifiers
URN: urn:nbn:se:kth:diva-202216DOI: 10.1063/1.4974297ISI: 000392836900009Scopus ID: 2-s2.0-85009999442OAI: oai:DiVA.org:kth-202216DiVA: diva2:1082997
Note

Funding text: The research at KTH was performed within the frame of Linnaeus Excellence Center for Advanced Optics and Photonics (ADOPT) and was financially supported by the Swedish Energy Agency (Contract No. 36652-1) and the Swedish Research Council (Contract No. 621-2013-4096). The work at UCSB was supported by the Solid State Lighting and Energy Electronics Center (SSLEEC). QC 20170320

Available from: 2017-03-20 Created: 2017-03-20 Last updated: 2017-11-29Bibliographically approved
In thesis
1. Impact of carrier localization on recombination in InGaN quantum wells with nonbasal crystallographic orientations
Open this publication in new window or tab >>Impact of carrier localization on recombination in InGaN quantum wells with nonbasal crystallographic orientations
2017 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The modern InGaN technology demonstrates high efficiencies only in the blue spectral region and low current operation modes. The growth of InGaN quantum wells (QWs) on nonbasal crystallographic planes (NBP) has potential to deliver high-power blue and green light emitting diodes and lasers. The emission properties of these QWs are largely determined by the localization of carriers in the minima of spatially inhomogeneous band potential, which affects the recombination dynamics, spectral characteristics of the emission, its optical polarization and carrier transport. Understanding it is crucial for increasing the efficiency of NBP structures to their theoretical limit.

In this thesis, the influence of carrier localization on the critical aspects of light emission has been investigated in semipolar  and nonpolar  InGaN QWs. For this purpose, novel multimode scanning near-field optical microscopy configurations have been developed, allowing mapping of the spectrally-, time-, and polarization-resolved emission.

In the nonpolar QW structures the sub-micrometer band gap fluctuations could be assigned to the selective incorporation of indium on different slopes of the undulations, while in the smoother semipolar QWs – to the nonuniformity of QW growth. The nanoscale band potential fluctuations and the carrier localization were found to increase with increasing indium percentage in the InGaN alloy. In spite to the large depth of the potential minima, the localized valence band states were found to retain properties of the corresponding bands. The reduced carrier transfer between localization sites has been suggested as a reason for the long recombination times in the green-emitting semipolar QWs. Sharp increase of the radiative lifetimes has been assigned to the effect of nanoscale electric fields resulting from nonplanar QW interfaces. Lastly, the ambipolar carrier diffusion has been measured, revealing ~100 nm diffusion length and high anisotropy.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2017. 67 p.
Series
TRITA-FYS, ISSN 0280-316X ; 2017:53
Keyword
InGaN, quantum well, semipolar, nonpolar, near-field microscopy, carrier localization, carrier transport, optical polarization
National Category
Condensed Matter Physics
Research subject
Physics
Identifiers
urn:nbn:se:kth:diva-214599 (URN)978-91-7729-505-1 (ISBN)
Public defence
2017-09-29, Hall C, Elektrum 229, Kista, 13:00 (English)
Opponent
Supervisors
Funder
Swedish Energy Agency, 36652-1Swedish Research Council, 621-2013- 4096
Note

QC 20170919

Available from: 2017-09-19 Created: 2017-09-18 Last updated: 2017-09-19Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textScopus

Authority records BETA

Marcinkevičius, SauliusUŽdavinys, Tomas Kristijonas

Search in DiVA

By author/editor
Ivanov, R.Marcinkevičius, SauliusUŽdavinys, Tomas Kristijonas
By organisation
Materials- and Nano Physics
In the same journal
Applied Physics Letters
Physical Sciences

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 19 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf