Abstract
We report determination of parameters in the nearest-neighbor sp3d5s* tight-binding (TB) model for nine binary compound semiconductors which consist of Al, Ga, or In and of P, As, or Sb based on the hybrid quasi-particle self-consistent GW (QSGW) calculations. We have used the determination parameters to calculated band structures and related properties of the compounds in the bulk phase relevant to mid-infrared applications and of the type-II (InAs)/(GaSb) superlattices. For the type-II (InAs)/(GaSb) superlattices with various superlattice periods, good agreement with photoluminescence measurements on the band gaps has been confirmed. Furthermore, two aspects of the band gap properties from other calculations have been reproduced: the band gap energies rising up to some superlattice periods and shrinking beyond them asymptotically. In both the bulk phase and the superlattices, erroneous flat valence bands have appeared within the nearest-neighbor sp3s* TB model. The present TB model has been eliminated these artifacts, potential obstacles to design advanced superlattices.
Highlights
The development of mid-infrared sensors in wavelength range from 3 to 20μm is actively underway [1,2,3,4,5], because the normal vibrational energies of many molecules overlap midinfrared
The properties are described slightly better by the sp3 d 5 s∗ model except for the Γ7v levels, probably because the exact analytic expressions which associate the properties with the TB parameters are unavailable as already mentioned
We report determination of parameters in the sp3 d 5 s∗ TB model for the nine binary compound semiconductors which consist of Al, Ga, or In and of P, As, or Sb based on the hybrid quasi-particle self-consistent GW (QSGW)
Summary
The development of mid-infrared sensors in wavelength range from 3 to 20μm is actively underway [1,2,3,4,5], because the normal vibrational energies of many molecules overlap midinfrared. Sensors made of HgCdTe have been conventionally used. This approach has disadvantages, containment of hazardous heavy metals, Hg and Cd [6], the requirement of large-scale equipment for cryogenic cooling. Type-II (InAs)/(GaSb) superlattices are expected to be alternative materials [7]. The type-II (InAs)/(GaSb) superlattice is characterized by larger electron and hole effective masses, which leads to reduction of dark current, lower sensitivity to compositional non-uniformity, and a wide ranging band gap accurately determined by controlling supertlattice period [8,9,10]. Toward high temperature operation of infrared sensors, band structure engineering is utilized to suppress Auger recombination [11,12,13]
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