Muonium in semiconductors: new discoveries and new questions

Abstract

Muonium centres in semiconductors, especially those newly reported, show widely different hyperfine constants and binding energies. Three reasonably distinct categories can be discerned, with very different implications for the electrical activity of hydrogen impurity or the use of hydrogen in the control of conductivity. The factors which might influence this variation in behaviour are considered; methods of determining the spatial extent of the electronic wave function are discussed, and a variety of new experiments proposed. This paper is dedicated to the memory of MCR Symons (1925–2002).