Identification of manganese trace impurity in GaN crystals by electron paramagnetic resonance

Abstract
We report on the first observation of electron paramagnetic resonance of manganese trace impurity in GaN crystals. The resolved hyperfine structure due to interaction with nuclei has been observed in GaN for the first time, allowing unambiguous identification of the impurity. Manganese exists in the charge state with electron spin S = 5/2 and occupies gallium sites in the GaN lattice. We found g = 1.999, and the fine structure parameter .