Dielectric functions and interband transitions of In1-xAlxSb alloys

Abstract

Pseudodielectric functions <epsilon > of In1-xAlxSb ternary alloy films were determined from 1.5 to 6.0 eV by spectroscopic ellipsometry. Overlayer effects were minimized by performing in situ chemical etching to more accurately determine intrinsic bulk dielectric responses. Critical-point (CP) energies of structures were determined from numerically calculated second energy derivatives. Where necessary, Brillouin-zone origins were identified by electronic band structure calculations done with the linear augmented Slater-type orbital method. These calculations also showed increasing separation of the E-2 and E-2&apos; CP structures with increasing Al-composition. (C) 2010 American Institute of Physics. [doi:10.1063/1.3488827]