CHARGE TRANSFER IN GALLIUM ARSENIDE

The transfer of electronic charge in GaAs is estimated by re-evaluation of the experimental results of Demarco and Weiss. Complete and suitable atomic scattering factors must be used in the interpretation of a single reflection. The Thomas-Fermi-Dirac statistical model is found to be more satisfactory then self-consistent field models. There is a transfer of electronic charge from As to Ga of 0·46 ± 0·05 electrons. The direction of charge transfer agrees with previous results for InSb. The magnitude of charge transfer may be compared favourably with estimates of effective ionic charge obtained from infra-red reflection measurements, where values of 0·43 and 0·51 electrons have been reported for GaAs. The direction of charge transfer agrees with the results of piezoelectric measurements on GaAs, where the magnitude of charge transfer was estimated to be 0·51 electrons.