Muonium states in II–VI zinc chalcogenide semiconductors

A systematic experimental study of muonium states in the binary compounds ZnSe, ZnS and ZnTe is presented. Deep muonium states are observed in ZnSe and ZnS but not in ZnTe. In ZnTe, only the diamagnetic signal is seen. The temperature dependence of the muonium and muon fractions is measured in the three materials by muon spin rotation and, for ZnTe, also by RF-μSR. In none of the three compounds any indication of the neutral donor state, known from ZnO, CdS and others, is found. We conclude that in the Zn chalcogenides the neutral (interstitial) muonium configuration is more stable than the neutral (anion bonded) shallow donor configuration. The significance of the results is discussed with respect to the behaviour of hydrogen.