Bandgap Variation and Miscibility Gaps of Thallium-Based Pseudo-Binary Alloys

Abstract

AbstractTo stimulate further research on the TI-based semiconductor alloys for long-wave infrared (LWIR) application, we carried out detailed calculations for the variation of band gaps versus lattice constants and the alloy miscibility gaps of cation-substituted pseudo-binary alloys. These results are used to identify promising TI-based LWIR alloys and the lattice-matched non-TI bearing alloys for possible substrates and passivation caps. Although all the six Tl-bearing pseudo-binary alloys studied can have a 0.1 eV band gap, none of these systems are lattice matched to a pure III-V compound. Five of these six alloys can have a non-TI-bearing lattice-matched ternary alloy as the substrate, but only two do not have a serious problem with the miscibility gap. When further considering the difficulty of incorporating TI with a large concentration, the only promising LWIR pseudo-binary alloy left is In1−xTlxAs with x≍0. 16.