3 Institute of Electron Technology, Al. Lotnikow 32/46, 02-668 Warsaw, Poland Optoelectronic properties of InAs/GaSb Optoelectronic properties of InAs/GaSb superlattices superlattices with asymmetric interfaces with asymmetric interfaces Elzbieta Machowska-Podsiadlo Elzbieta Machowska-Podsiadlo 1 , 1 Rzeszow University of Technology, Department of Electronics Fundamentals, Al. Powstancow Warszawy 12, 35-959 Rzeszow, Poland, [email protected]Slawomir Sujecki Slawomir Sujecki 2 , Trevor Benson , Trevor Benson 2 , , 2 The University of Nottingham, The George Green Institute for Electromagnetics Reasarch, University Park, Nottingham NG7 2RD, UK Agata Jasik Agata Jasik 3 , Maciej Bugajski , Maciej Bugajski 3 3 , Kamil Pierscinski , Kamil Pierscinski 3 TMCSIII Conference TMCSIII Conference 18 18 th th -20 -20 th th Jan 2012, Jan 2012, School of Electronic and Electrical Engeneering, School of Electronic and Electrical Engeneering, University of Leeds, UK University of Leeds, UK COST-STSM-MP0702-8103 COST-STSM-MP0702-8103 2 nd nd -27 -27 th th of May, 2011 of May, 2011 European Cooperation in the field of European Cooperation in the field of Scientific and Technical Research Scientific and Technical Research Grant PBZ-MNiSW 02/I/2007 Grant PBZ-MNiSW 02/I/2007 „ The advanced technologies The advanced technologies for infrared semiconductor for infrared semiconductor optoelectronics” optoelectronics” The work was supported by: The work was supported by: Grant 5070/B/T02/2011/40 Grant 5070/B/T02/2011/40 „ „ Methods of design and optimalization of the type-II Methods of design and optimalization of the type-II InAs/GaSb superlattices for applications in the InAs/GaSb superlattices for applications in the infrared detectors” infrared detectors” founded by The National Science founded by The National Science Center Center .
13
Embed
Optoelectronic properties of InAs/GaSb superlattices with asymmetric interfaces
Optoelectronic properties of InAs/GaSb superlattices with asymmetric interfaces. Elzbieta Machowska-Podsiadlo 1 ,. The work was supported by:. European Cooperation in the field of Scientific and Technical Research. Grant 5070/B/T02/2011/40 - PowerPoint PPT Presentation
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
3Institute of Electron Technology, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
Optoelectronic properties of InAs/GaSb superlattices Optoelectronic properties of InAs/GaSb superlattices with asymmetric interfaceswith asymmetric interfaces
2The University of Nottingham, The George Green Institute for Electromagnetics Reasarch, University Park, Nottingham NG7 2RD, UK
Agata JasikAgata Jasik33, Maciej Bugajski, Maciej Bugajski3 3 , Kamil Pierscinski, Kamil Pierscinski33
TMCSIII Conference TMCSIII Conference 1818thth-20-20thth Jan 2012, Jan 2012,School of Electronic and Electrical Engeneering,School of Electronic and Electrical Engeneering,University of Leeds, UKUniversity of Leeds, UK
COST-STSM-MP0702-8103COST-STSM-MP0702-8103 22ndnd-27-27thth of May, 2011 of May, 2011
European Cooperation in the field of European Cooperation in the field of Scientific and Technical ResearchScientific and Technical Research
Grant PBZ-MNiSW 02/I/2007Grant PBZ-MNiSW 02/I/2007„„The advanced technologies The advanced technologies for infrared semiconductor for infrared semiconductor optoelectronics”optoelectronics”
The work was supported by: The work was supported by:
Grant 5070/B/T02/2011/40Grant 5070/B/T02/2011/40„ „ Methods of design and optimalization of the type-II Methods of design and optimalization of the type-II InAs/GaSb superlattices for applications in the InAs/GaSb superlattices for applications in the infrared detectors” infrared detectors” founded by The National Science founded by The National Science CenterCenter..
Advantages of the type-II superlattices:Advantages of the type-II superlattices:
- better structuralstructural stabilitystability of the material,
- greater uniformity of the structureuniformity of the structure as compared to MCT alloys – the
possibility to form the Focal Plane Arrays (FPA),
- compatibilitycompatibility with the III/V materials technologyIII/V materials technology,
- possibility to detect IR at high temperaturesto detect IR at high temperatures,
- the lack of the toxic elementsthe lack of the toxic elements like mercury (Hg) and cadmium (Cd).
The need The need to know to know the SL band the SL band structurestructure
OUTLINE
• Band diagram and parameters of the type-II superlattices.Band diagram and parameters of the type-II superlattices.
• Summary.Summary.
3/12
• SL structure - possible types of IFs.SL structure - possible types of IFs.
- Influence of the band offset energy on the absorption edge of the SLs with symmetric and asymmetric IFs;
- Parameters of the calculations, transition energies for the SLs with different thickness of the layers;
• ResultsResults
• The four-band Kane model CB-HH-LH-SO andThe four-band Kane model CB-HH-LH-SO and k kpp method, method, the nonparabolicity effects, strain built-in the SL structure, HH-LH states mixing at the IFs of the SL.
- Influence of the number of „InSb-like” IFs in the SL on the band structure and transition energy;
- Calculated cut-off wavelength and the PL spectrum measured for (InAs)10/(GaSb)10 x30 SL sample with two types of IFs in the structure.
offsetEoffsetE
T=0K T=77K T=300K
EG InAs
EG GaSb
410
813.3
414
800
356
725
CB
VB
InAs GaSb
a2b2
InAs GaSb InAs
Band diagram and parameters of the type-II superlattice4/12
Type I superlattices
eV42.1
GE eV80.1
GECB
VB
3.0x
GaAs AlxGa1-xAs
3.6nm.42 nm6.34.2
Type II superlattices
T=0KmeV3.953
meV410
0
meV140
meV410
GE
meV3.813
GE
E. E. PlisPlis, , 20072007
F. Szmulowicz, F. Szmulowicz, PRB PRB 6969, 2004, 2004
F. Szmulowicz, Eur. F. Szmulowicz, Eur. J. Phys. J. Phys. 2525, 2004, 2004
Institute of Electron Technology, WarsawInstitute of Electron Technology, Warsaw
5.30m 233.87meV
only InSb
IFs
only GaAs IFs
every 4th InSb IF
every 2nd InSb IF
5.36m231.2meV
5.33m232.5meV
- ResultsResults of calculations are of calculations are sensitive to the density of nodes in the discretization meshsensitive to the density of nodes in the discretization mesh – – simulations should be performed with the mesh nodes distanced bysimulations should be performed with the mesh nodes distanced by 1ML rather than 2ML.1ML rather than 2ML.
Summary
12/12
- kkpp method method and and the four-band Kane modelthe four-band Kane model CB-HH-LH-SO CB-HH-LH-SO (which takes into account the nonparabolicity effects, strain built-in the SL and HH-LH (which takes into account the nonparabolicity effects, strain built-in the SL and HH-LH wavefunctions mixing at the IFs in the structure)wavefunctions mixing at the IFs in the structure) allow to calculate the energy band structure of the SLs with symmetric and asymetric IFs allow to calculate the energy band structure of the SLs with symmetric and asymetric IFs and allow to determine and allow to determine the edge of the absorptionthe edge of the absorption of such structures. of such structures.
- The change of The change of EEoffsetoffset from 140 to 150 meV shifts the energy of HH from 140 to 150 meV shifts the energy of HH11-CB-CB11 transition transition
of the SLs with symmetric and asymmetric IFs of the SLs with symmetric and asymmetric IFs by about 7-8meVby about 7-8meV which gives which gives the shifts of the cut-off wavelengths by about 0.1-0.3the shifts of the cut-off wavelengths by about 0.1-0.3m.m.
- Good agreement of the calculated cut-off wavelength Good agreement of the calculated cut-off wavelength 5.365.36mm ((EEHH-CBHH-CB=231.2meV)=231.2meV) and and
the absorption edge found from the experimental data the absorption edge found from the experimental data ((cut-offcut-off==5.305.30m, m, EEHH-CBHH-CB=233.87meV)=233.87meV)
which were obtained forwhich were obtained for (InAs)(InAs)10 10 /(GaSb)/(GaSb)10 10 x 30x 30 superlattice superlattice. .
The SL sample was grownThe SL sample was grown in the MBE equipment and in the MBE equipment and the PL spectrum was measured the PL spectrum was measured with the use of FTIR spectrometer with the use of FTIR spectrometer at The Institute of Electron Technology in Warsaw. at The Institute of Electron Technology in Warsaw.