Photoluminescence and optically-detected cyclotron resonance experiments were performed on unintentionally doped multi quantum-well structures. It was shown that donor-type shallow impurities contributed to the photoluminescence emission from undoped quantum wells of the multi quantum-well structures. The photoluminescence emission of a neutral donor bound exciton was identified, and the origin of the donor species in CdTe and ZnCdSe quantum wells was considered. The optically-detected cyclotron resonance data indicated that these donor impurities limited the mobility of 2-dimensional carriers. It was also shown that the energy transfer between localized excitons and donor bound excitons was not efficient.

M.Godlewski, J.P.Bergman, B.Monemar, B.Koziarska, A.Suchocki, G.Karczewski, T.Wojtowicz, J.Kossut, A.Waag, D.Hommel: Materials Science Forum, 1995, 196-201, 455-60