We have investigated muonium (Mu) defect centers in single crystal AlN as an analog for atomic hydrogen impurities. A nitrogen-related muon level-crossing resonance is associated with a static center formed by trapping of a mobile Mu impurity at another defect. This trapped Mu is released above 800K.Muon spin depolarization data imply that both Mu0 and ground-state Mu+ centers are mobile. Strong correlations between growth of the trapped Mu resonance and Mu0 motion and transformation rates above 400K imply that Mu0 is the more likely precursor in that region.
Source: Physica B: Condensed Matter