Carbon tetrabromide carbon doping of molecular beam epitaxial (GaAs) films

GaAs films were doped with carbon up to a hole concentration of 1.3×1020 cm−3 using CBr4 vapor. The material quality of the heavily doped films was found to be better than that obtained using evaporated carbon. Improvements at the highest doping levels include better surface morphology, higher hole mobilities, significantly stronger photoluminescence, and near unity substitutional incorporation. Doping pulses created using CBr4 exhibited abrupt transitions. From the results it is suggested that the material quality of the films doped with evaporated carbon are degraded at high doping levels due to surface combination of reactive carbon species.