Electrical Properties of Sulfur-Doped Gallium Phosphide

Abstract

Sulfur-doped n-type GaP crystals with carrier concentrations in the range between 6.0×1016 and 5.7×1018 cm−3 have been grown by an epitaxial-growth technique. Hall measurements on these crystals have been carried out over the temperature range from 4.2°–400°K. The room temperature electron mobility in GaP depends weakly upon the donor concentration. The temperature dependence of electron mobility in the higher temperature region indicates that polar mode lattice scattering is dominant. In the lower temperature region, ionized impurity scattering does not play an important role. Impurity conduction is observed below about 60°K. The impurity conduction process changes from hopping to metallic form with increasing doping level. This critical transition concentration is 2.1×1018 cm−3 in GaP.