The use of SnTe as the source of donor impurities in GaAs grown by molecular beam epitaxy

The use of SnTe as a source of donor impurities in the growth of n-type GaAs by molecular beam epitaxy (MBE) is investigated. Net carrier concentrations n between ∼1015 and ∼1018 cm−3 have been obtained with corresponding mobilities of ∼38 000 and 2100 cm2 V−1 sec−1 at 77 °K. Sharp changes in donor concentration have been obtained with no evidence for Sn accumulation at the surface. However, at higher donor concentrations (∼1018 cm−3) Te is found to accumulate at the surface.