A dominant electrical defect in GaAs

Several as-grown Bridgman and Czochralski GaAs crystals, with dominant electrical levels from 0.13–0.20 eV below the conduction band, have been studied by the temperature-dependent Hall-effect, spark-source mass spectroscopy, and secondary-ion mass spectroscopy. It is shown that no impurity is of a sufficient concentration to account for these levels, and therefore they are composed of single or multiple defects. The detailed nature of the defects has not yet been established but may involve an As vacancy. It is believed that this is the first time that a dominant electrically active center has been shown to be a pure defect in any as-grown semiconductor.