POINT-DEFECTS IN III-V MATERIALS GROWN BY MOLECULAR-BEAM EPITAXY AT LOW-TEMPERATURE

The present understanding of the point defects in GaAs and InP grown n by molecular beam epitaxy at low temperature (LT) is briefly reviewed . New results on vacancies and ion-type accepters obtained by positron annihilation are given. Depending on the growth temperature. Ga vacan cies or small vacancy clusters are seen in LT GaAs in the concentratio n range 10(18) Cm-(3). No signal from Ga antisites is found. The LT Ln P layers contain vacancies. identified as In vacancies, in the concent ration range 10(18) cm-(3). Ion-type acceptors, probably In antisites, are also seen in concentrations of 10(17)cm-(3). The annealed layer c ontains small vacancy clusters.