Shallow donor state of hydrogen in In2O3 and SnO2: Implications for conductivity in transparent conducting oxides

Abstract

Muonium, and by analogy hydrogen, is shown to form a shallow-donor state in In2O3 and SnO2. The paramagnetic charge state is stable below similar to 50 K in In2O3 and similar to 30 K in SnO2 which, coupled with its extremely small effective hyperfine splitting in both cases, allows its identification as the shallow-donor state. This has important implications for the controversial issue of the origins of conductivity in transparent conducting oxides.