Positron studies of MBE-grown gallium nitride

Defect distributions in thin GaN films on GaAs substrates have been assessed. Significant trapping at the interfaces has been observed. The analysis program ROYPROF has been employed to obtain a new parameter Li. to characterise the interface. It is suggested that this parameter is widely adopted. Anomalous positronium production was indicated. q1999 Elsevier Science B.V. All rights reserved.