The H passivation effect of Zn was studied by monitoring donor-acceptor pair luminescence bands. The existence of a critical pair-separation distance was detected, within which neutralization by H was almost entirely suppressed by the presence of a nearby donor. This phenomenon was reflected by a relative enhancement of the intensities of the discrete pair lines, as compared to that of the remote pair band in S-Zn pair emission. Further evidence was provided by the fact that the intensity reduction in the O-Zn band was much smaller than that predicted by calculations which assumed a random neutralization of Zn acceptors. It was suggested that the suppression was due to the Coulomb potential of a nearby donor atom, and was consistent with the concept that the principal diffusing form of H was positively charged.

Y.Mochizuki, M.Mizuta: Materials Science Forum, 1992, 83-87, 575-80