AUTO-DOPING OF GA IN ZNSE GAAS LAYERS GROWN AT LOW-TEMPERATURES BY POST-HEATED MOLECULAR-BEAM EPITAXY/

The donor species in Li acceptor-doped ZnSe epilayers grown on GaAs su bstrate are determined by means of the secondary ion mass spectroscopy (SIMS). The compositional depth profile by the SIMS points out that a large amount of Ga atoms are incorporated into the ZnSe epilayer rega rdless of doping. In doped epilayers, the Ga atoms are concentrated at the region where the Li atoms are doped. We conclude that Ga atoms or iginating from the droplets due to the thermal cleaning of the substra te are most likely the major donor species.