A review was presented of recent work on the properties of H defect centres in this group-III nitride, together with relevant studies involving µSR spectroscopy (muon spin rotation, relaxation and resonance). Particular attention was paid to results which were obtained by means of a form of nuclear quadrupole resonance. Implanted positive muons were used to model the behaviour of interstitial protons. The resultant defect centres exhibited both metastability and bistability. In n-type material, cage-site positive ions were stable up to 200K. Above this temperature, they captured electrons and converted to

negatively charged centres which were analogous to hydride ions and relocated to sites which were anti-bonded to Ga. The latter escaped from the cage sites at around 600K, with an activation energy of 1.5eV, and joined more mobile negative ions which diffused via channel sites; with an activation energy of 0.65eV. Data on the neutral paramagnetic centre suggested that H might act as a shallow-donor in InN.

Hydrogen in Group-III Nitrides, Studied by Muon Spin Resonance. S.F.J.Cox, R.L.Lichti, E.A.Davis: Journal of Physics D, 2002, 35[3], 586-90