Tailoring InAs/Ga1-xInxSb superlattices for long-wavelength IR applications

✍ Scribed by J.H. Roslund; T.G. Andersson

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 519 KB
• Volume: 16
• Category: Article
• ISSN: 0749-6036
• DOI: 10.1006/spmi.1994.1114

✦ Synopsis

A systematIc study has been carned out on the design of long-wavelength Infrared detector matenals from InAs/GaSb and InAs/GalnSb superlatllces with absorpl1on energies below 250 meV. i.e .\ > Slim. The influence from layer thicknesses and alloy composition on cut-off wavelength and opllcal matnx element has been analysed. A three-band envelopefunction model Including strain effects was used to calculate conduction-band electron and valence-band light-hole states, while an effective-mass approximation wa~ used to descnbe heavy-hole states. In order to achieve useful absorption coeffiCIents. the period of such superlattices must be less than typically 20 monolayers. Calculations revealed that the absorptIon can be increased Wllh almost unaffected cut-off wavelength by redUCing the GalnSb thIckness. The effects of including a small amount of In In the GaSb in order to reach longer wavelengths were studied. One conclusion is that although it makes longer wavelengths pOSSible. It also makes the cut-off wavelength much more sensitive to monolayer and compositIOn fluctuations.