An investigation was made of the minority carrier lifetime in p-type liquid-phase epitaxial layers. It was found that the lifetime was dominated by the Shockley-Read-Hall mechanism, whose recombination centres were closely associated with acceptor energy levels. The lifetime and acceptor activation levels were compared for 2 types of p-type layer having differing acceptors. One type was a conventional Hg-vacancy doped layer, and the other was a Ag-doped layer. In the case of p-type layers which were doped with Hg vacancy acceptors, the minority carrier lifetime was very short due to Shockley-Read-Hall recombination centres which existed 0.02eV above the valence band. This trap energy was slightly larger than that of the acceptor activation energy. When the layers were doped with Ag, the Shockley-Read-Hall center disappeared and the lifetime increased. In this case, the lifetime was dominated by another Shockley-Read-Hall center of 0.005eV; which was again near to the acceptor level of the host material. It was concluded that Shockley-Read-Hall centres in Hg-vacancy doped layers originated from the vacancy itself and had no relationship with crystal defects. The use of Ag replacement appeared to cause the only energy state change, for vacancy-related Shockley-Read-Hall centres, in which the energy shift corresponded to the acceptor level shift.

Acceptor Level Related Shockley-Read-Hall Centres in p-HgCdTe. H.Nishino, K.Ozaki, M.Tanaka, T.Saito, H.Ebe, Y.Miyamoto: Journal of Crystal Growth, 2000, 214-215, 275-9