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
Minority current distribution in InGaAs/GaAs transistor-vertical-cavity surface-emitting laser
KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
Show others and affiliations
2013 (English)In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 102, no 19, 191101- p.Article in journal (Refereed) Published
Abstract [en]

We compare experimental data with three-dimensional numerical calculations of the local minority current in an InGaAs/GaAs transistor vertical-cavity surface-emitting laser at different bias levels. It is demonstrated that lateral potential variations within the device greatly affect the transistor operating conditions. As a result, it locally operates in the active mode in the center of the device, allowing for efficient stimulated recombination, while it globally operates in the saturation regime as reflected by the measured current-voltage characteristics. This allows for excellent laser performance, including mW-range output power, sub-mA threshold base current, and continuous-wave operation well above room temperature.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2013. Vol. 102, no 19, 191101- p.
Keyword [en]
current distribution, gallium arsenide, heterojunction bipolar transistors, III-V semiconductors, indium compounds, integrated optoelectronics, laser beams, laser cavity resonators, laser modes, numerical analysis, optical saturation, quantum wells, surface emitting lasers
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
URN: urn:nbn:se:kth:diva-122997DOI: 10.1063/1.4803175ISI: 000320440800001Scopus ID: 2-s2.0-84877935923OAI: oai:DiVA.org:kth-122997DiVA: diva2:624270
Funder
Swedish Research Council, 2010-4386
Note

QC 20130626

Available from: 2013-05-30 Created: 2013-05-30 Last updated: 2017-12-06Bibliographically approved
In thesis
1. GaAs based Vertical-Cavity Surface-Emitting Transistor-Lasers
Open this publication in new window or tab >>GaAs based Vertical-Cavity Surface-Emitting Transistor-Lasers
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The ever-increasing demand for broadband capacity of the global optical communication networks puts enormous requirements on the semiconductor laser used in the optical transmitter. Industrial standard bodies for optical communication project requirements of single-channel data rates as high as 100 Gbit/s around year 2020. This is a significant step with respect to today's technology which is only at the verge of introducing 25 Gbit/s emitters. The preferred light source for these applications is the vertical-cavity surface-emitting laser (VCSEL) which can offer cost- and power-efficient directly modulated operation. However, it has proven extremely difficult to push the modulation bandwidth of VCSELs beyond 30 GHz and radically new device concepts are demanded to meet the upcoming needs. One such new device paradigm consists of the transistor laser which is the fusion of a semiconductor laser and a high-speed heterojunction bipolar transistor (HBT) into a single device, with potential significant advantages in modulation bandwidth, noise properties and novel functionality by virtue of the three-terminal configuration. The present thesis deals with the design, fabrication and analysis of vertical-cavity surface-emitting transistor-lasers (T-VCSELs), a device previously not realized or investigated in great detail.

GaAs-based T-VCSELs are investigated both theoretically and experimentally. A three-dimensional model is set up with a commercial software package and used for performance predictions and analysis as well as design and optimization purposes. It is concluded that a T-VCSEL biased in the common-base configuration may have a bandwidth surpassing those of conventional diode-type VCSELs or a T-VCSEL itself in the common-emitter configuration. Fabricated T-VCSELs make use of an epitaxial regrowth design to homogeneously integrate an AlGaAs/GaAs HBT and an InGaAs/GaAs VCSEL. An intracavity contacting scheme involving all three terminals, undoped distributed Bragg reflectors and modulation doping are used to ensure a low-loss laser structure. The first generation of devices showed sub-mA range base threshold current in combination with a high output power close to 2 mW but did not fulfill the requirements for a fully operational transistor laser since the transistor went into saturation before the onset of lasing (IBsat<IBth). From numerical simulations this premature saturation was demonstrated being due to a lateral potential variation within the device and large voltage drops along the base and collector regions. As a remedy to this problem the base region was redesigned for a reduced resistance and transistor current gain, and the saturation current could thereby be extended well beyond threshold. These devices showed excellent transistor-laser characteristics with clear gain-compression at threshold, mA-range base threshold current, mW-range output power, high-temperature operation to at least 60°C, low collector-emitter offset voltage and record-low power dissipation during lasing. Furthermore, the collector-current breakdown characteristics was investigated in some detail and it is concluded that this, in contrast to previous models, presumably not is due to an intracavity photon reabsorption process but rather to a quantum-well band-filling effect.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2014. vii, 64 p.
Series
TRITA-ICT/MAP AVH, ISSN 1653-7610 ; 2014:16
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electrical Engineering
Identifiers
urn:nbn:se:kth:diva-156841 (URN)978-91-7595-363-2 (ISBN)
Public defence
2014-12-19, Sal/hall C, Electrum, KTH-ICT, Kista, 10:00 (English)
Opponent
Supervisors
Note

QC 20141203

Available from: 2014-12-03 Created: 2014-12-02 Last updated: 2015-04-13Bibliographically approved

Open Access in DiVA

APL_102_191101(1673 kB)206 downloads
File information
File name FULLTEXT01.pdfFile size 1673 kBChecksum SHA-512
c95af82006331a7aa3fe0a336805560793204eb550606fda843cd80fad40878f394b954ff431d894614d44e5ca03fd20cab2fd92183cb60393a48041a03bb867
Type fulltextMimetype application/pdf

Other links

Publisher's full textScopusPublisher's website

Authority records BETA

Hammar, Mattias

Search in DiVA

By author/editor
Xiang, YuYu, XingangBerggren, JesperZabel, ThomasHammar, Mattias
By organisation
Integrated Devices and Circuits
In the same journal
Applied Physics Letters
Electrical Engineering, Electronic Engineering, Information Engineering

Search outside of DiVA

GoogleGoogle Scholar
Total: 206 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 103 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