The positron lifetime spectroscopy of Zn-doped material revealed the presence of a defect with a positron lifetime of about 330ps in samples where the carrier concentration had saturated. This lifetime was attributed to a complex which involved vacancies and Zn atoms. Positron lifetime and Hall-effect measurements of annealed samples, and those made at temperatures below 20K, suggested that this complex had a (-/0) level near to the bottom of the band-gap and that the concentration of these complexes was less than 1017/cm3. It was concluded that these complexes could not alone account for the observed discrepancy between the carrier concentration and the Zn concentration in very heavily Zn doped InP.

J.Mahony, P.Mascher: Materials Science Forum, 1995, 196-201, 1661-6