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

摘要

We report the complex dielectric function of InSb for temperatures from 31 to 675 K 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+Δ_1, E_0′, Δ_5~(cu)- Δ_5~(vu) (0.35, 0, 0), E_0′+Δ_0′, Δ_5~(cl)-Δ_5~(vu) (0.35, 0, 0), E_2, E_2′, E_2+Δ_2, E_2'+Δ_2, E_1', E_1+Δ_1′, and E_1'+Δ_1'+Δ_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 100 K and those of the E_0', E_0'+Δ_0, E_2', E_2+Δ_2, E_2'+Δ_2, E_1'+Δ1', and E_1′+Δ_1'+Δ_1 transitions have not previously been reported.