Temperature dependence of the dielectric functions and the critical points of InSb by spectroscopic ellipsometry from 31 to 675K

We report the complex dielectric function of InSb for temperatures from 31 to 675K and energies from 0.74 to 6.42 eV. The spectra were obtained by rotating-compensator spectroscopic ellipsometry on bulk InSb. The critical point (CP) energies were determined using numerically calculated second energy derivatives of the data. At low temperature, the CP structures are blue-shifted and significantly sharpened relative to those seen at high temperature. The temperature dependence of the E-1, E-1+Delta(1), E-0', Delta(cu)(5)-Delta(vu)(5) (0.35, 0, 0), E-0'+Delta(0)', Delta(cl)(5)-Delta(vu)(5) (0.35, 0, 0), E-2, E-2', E-2+Delta(2), E-2'+Delta(2), E-1', E-1'+Delta(1)', and E-1'+Delta(1)'+Delta(1) CPs was determined by fitting to a phenomenological expression that contains the Bose-Einstein statistical factor or to a linear equation. In particular, temperature dependences of CPs below 100K and those of the E-0', E-0'+Delta(0)', E-2', E-2+Delta(2), E-2'+Delta(2), E-1'+Delta(1)', and E-1'+Delta(1)'+Delta(1) transitions have not previously been reported. (C) 2013 AIP Publishing LLC.