Ga-related defect in as-grown Zn-doped GaN: An optically detected magneticresonance study

A detailed study of as-grown Zn-doped GaN employing optically detected magn etic resonance (ODMR) spectroscopy is presented. Besides the well-known ODM R spectra of an effective-mass-like donor and Zn acceptor, a positive ODMR signal of an S = 1/2 paramagnetic center was observed when monitoring the d ominating blue luminescence band peaking at 2.8 eV. The involvement of a si ngle Ga nucleus in the defect center is revealed from the rather well-resol ved hyperfine interactions involving the isotopes Ga-71 (39.9%) and Ga-69 ( 60.1%), both with nuclear spin I = 3/2. The C-3 nu symmetry, the hyperfine interaction and the defect formation suggest a Ga-related complex nature of this center.