Temperature Dependence of the Energy Gap in GaAs and GaP

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Abstract
Absorption measurements from 300°–973°K for GaAs and to 1273°K for GaP were made in order to determine the energy gap Eg of these materials at high temperatures. These data, together with previously published results, show that the energy‐gap width may be represented by a simple expression for all temperatures. As a function of the absolute temperature T, the direct gap in GaAs is given by Eg=1.522−5.8×10−4T2 / (T+300) eV, and the indirect gap in GaP is given by Eg=2.338−6.2×10−4T2 / (T+460) eV. The general form of the expression for the energy gap is Eg=Eg(0)−aT2 / (T+β), where Eg(0) is the energy gap at 0°K, β is approximately the 0°K Debye temperature, and a is an empirical constant.