μSR research in semiconductors

Muon and muonium states in semiconductors especially silicon and germanium, have been the subject of μSR research from the birth of the μSR technique until the present. They are now under active investigation at at least three laboratories. Three different electronic states of the muon impurity have been firmly identified in silicon and more tentatively in germanium. This research has produced a significant amount of published literature which, due to the span of time and distance between the various experiments, shows large differences in technique, emphasis and style. The author attempts to present a coherent view of this literature distinguishing the well-understood effects from those not understood. (Auth.)