Room-temperature photoreflectance and photoluminescence of heavily Si-doped GaAs

Abstract

Room-temperature photoreflectance (PR) and photoluminescence (PL) spectra in heavily n-doped G&U were compared. It was found that for highly degenerate semiconductors the critical energy measured by the PR equals to the peak energy of the PL spectrum. When Fermi level lies below the conriIlction-bartd minimum, the PR spectra revealed the band-gap energy as well as the energy E,,, at which the electron concentration per unit energy in the donor band becomes maximum, and this mnsimum was observed to merge in the conduction-band at about 3X lOI cm -3 electron concentration.