Band alignments and offsets in In(As,Sb)/InAs superlattices

Abstract

The band alignments and band offsets were investigated for In͑As,Sb͒/InAs superlattices of various periods and compositions. Magnetoabsorption experiments allowed identification of subband energies and in-plane reduced masses. Using an 8ϫ8 k•p band-structure calculation which takes account of nonparabolicity, valence subband mixing, and strain effects, we are able to fit calculated absorption curves to transition energies and reduced masses. Comparison of fits on several samples confirm that the electrons lie in the In͑As,Sb͒ layer and the holes in the InAs layer. By using the fitted curve offsets, we are able to calculate the fractional conduction-band-offset parameter, Q c , which for a type-II heterostructure can be greater than 1 and which we found to be 2.

Magnetotransport and Magnetooptics of InAs1-xSbxand Heterojunctions Combinations Formed Between InAs and GaSb, AlSb Or InAs1 -xSbx

“…The band offsets for the InΑs/ΙnΑs 1 -x Sbx superlattice system are the subject of some controversy with different groups variously putting forward type HA and type ΙIΒ alignments [1,2] on the basis of interband magnetoabsorption experiments performed at relatively low fields (< 10 T). In one case type I alignment coupled with strong narrowing of the band gap induced by Cu-Pt ordering in the alloy has also been proposed [3].…”

Computer modeling of MWIR single heterojunction photodetector based on mercury cadmium telluride

“…The Newton-Richardson iteration method has used to solve five nonlinear decoupled equations. The Newton-Richardson based method improves the efficiency of the iteration [12][13][14][15][16][17][18][19][20].…”

“…This is because of the fact that the material properties of MCT can be tailored over a wider range by using the mole fraction (x) of cadmium as a variable parameter. An extensive review of the longwavelength IR photodetectors (8)(9)(10)(11)(12)(13)(14) lm) based on MCT and their performance vis-à-vis long-wavelength photodetectors based on quantum-well (QW) structures has been carried out by Shen [2].…”

“…III-V, II-VI and IV-VI alloy semiconductors are very attractive for fabrication of infrared photodetectors. While SWIR (1-2 lm) region has been dominated by III-V alloys (InGaAs, InAsSb, InGaSb), mercury cadmium telluride (MCT) is the one of the most prominent semiconductor material for fabrication of MWIR (2-5 lm) and LWIR (8)(9)(10)(11)(12) lm) photodetector for optical detection [1][2][3][4]. This is because of the fact that the material properties of MCT can be tailored over a wider range by using the mole fraction (x) of cadmium as a variable parameter.…”

“…IR photodetectors can be realized in the heterojunction form so as to exploit the two atmospheric windows MWIR (2-5 lm) and LWIR (8)(9)(10)(11)(12) lm) of electromagnetic spectrum. The basic advantages of heterostructure photodetector include low power dissipation, low noise figure, fast response speed and potential for a more uniform spatial distribution for minority carrier transportation.…”