Effect of high doping on the photoluminescence edge of GaAs and InP

Abstract
A theoretical method for calculating the variation of optical transition energy Eg,opt in semiconductors with heavy n doping is presented. The calculations based on the Moss–Burstein shift and band-gap shrinkage take into account both exchange and Coulomb interactions, the latter being calculated for nonparabolic bands. A comparison with the experimental values of Eg,opt for heavily n-doped GaAs and InP shows good agreement over wide ranges of temperature and doping and can satisfactorily explain photoluminescent emission at energies up to 1.65 eV in GaAs (1.8 °K) and 1.91 eV in InP (300 °K).