Selenium doping of molecular beam epitaxial GaAs using SnSe2

Abstract

The feasibility of using SnSe2 as a source of selenium for the n-type doping of molecular beam epitaxial GaAs layers is demonstrated. Doping levels between 6×1014 and 7×1018 cm−3 have been achieved and no surface accumulation of selenium at the high doping concentrations was observed. Low temperature photoluminescence studies show that the excitonic emission broadens and shifts to higher energy with increasing doping concentration in a similar way to that observed in tellurium-doped GaAs. The half-width of the emission peak may be used to estimate the doping level of Se-doped layers on n+ substrates down to a concentration of about 2×1016 cm−3.