In Situ Arsenic Doping of CdTe/Si by Molecular Beam Epitaxy

p-Type doping of the absorbed layer has been a significant challenge for CdTe solar cells. In this work, we report on in situ arsenic doping of molecular beam epitaxy (MBE) CdTe grown on Si(211) and the use of a cadmium overpressure to enhance incorporation. When growing CdTe:As without a Cd overpressure, extremely high As fluxes are required to achieve noticeable amounts of arsenic incorporation. By supplying a Cd flux during growth, the As incorporation increases by an order of magnitude. By including a Cd overpressure during growth, we have obtained single-crystal CdTe:As films with As incorporation concentration of . An activation anneal was performed on these films in a rapid thermal annealing furnace, resulting in p-type layers with net carrier concentration of similar to 5 x 10(16) cm(-3).