Hall-Effect Levels Produced in Te-Doped GaAs Crystals by Cu Diffusion

Hall-effect measurements have been made on Te-doped GaAs crystals diffused with known amounts of 64Cu sufficient to convert the crystals to p-type. Energy levels are found above the valence band at 0.123±0.005 eV, 0.145±0.005 eV, 0.166±0.005 eV, 0.19±0.005 eV, and 0.43±0.01 eV. An analysis of the Hall data has been made by means of computer programs. The results may be summarized as follows: (1) Ga vacancies produced during the Cu diffusion associate with and neutralize Te as a compensating center. (2) The ionization energy of the TeCuGa pair is 0.19 eV rather than 0.166 eV as suggested previously.