Deep-level transient spectroscopy was used to investigate defects in N-doped layers which had been deposited, by means of molecular beam epitaxy, onto GaAs substrates. At least 3 prominent levels (Hl, H3, H4) were found in the lower half of the band-gap; having thermal activation energies of 0.31, 0.63 and 0.94 to 0.99eV, respectively. A comparison with previous work showed that, apart from H3, these were new levels. No obvious correlation between these hole levels and N doping could be found. It was tentatively suggested that the Zn:Se ratio during growth, which had differed in previous studies, might be an important factor in accounting for differences in the deep-level content.

U.S.Qurashi, M.Z.Iqbal: Semiconductor Science and Technology, 1997, 12[12], 1615-8