Journal of Physics Condensed Matter, vol.16, no.3, pp.325-331, 2004 (SCI-Expanded)
Muon spin depolarization measurements in a zero applied magnetic field confirm the existence of a shallow muonium (Mu) donor in InN, consistent with earlier transverse-field muon spin precession results. The zero-field data imply two Mu(+) centres in InN, similar to those associated with channel and cage sites in GaN. The zero-field results provide strong evidence that the shallow Mu(0) ionizes to Mu(+) at its lowest-energy location. We argue that data on Mu in the III-V nitrides, taken in total, support the assignment of a wurtzite channel location to the shallow hydrogen donor in InN. The present results yield 15.4 +/- 2 meV below the conduction band edge for the donor level depth.