Determination of charge carrier concentration from low-field electroreflectance spectra

The conditions for carrier concentration determination in semiconductors from low-field Schottky barrier electroreflectance studies are theoretically analysed and expressions are given for obtaining besides broadening parameters and critical point energies the amplitude of electroreflectance signals which is directly related to carrier concentration. The procedure is applied to low-field electroreflectance measurements on GaAs1−xPx epitaxial layers with different charge carrier concentration. The Schottky barriers are produced by evaporating Au. The measurements revealed the theoretically predicted linear relationship between the electroreflectance signal height and the charge carrier concentration.