Impurity-related luminescence of homoepitaxial GaN studied with high magnetic fields

Recent magnetoluminescence results obtained for homoepitaxial GaN layers ar e presented. The neutral impurity-bound excitons and donor-acceptor pair em ission lines have been studied in magnetic fields up to 27 T. Low-temperatu re luminescence spectra have been measured with the magnetic field parallel and perpendicular to the hexagonal c-axis of the GaN layers. Experimental results allowed us to evaluate diamagnetic shifts, effective g-factors of e lectrons and holes involved in neutral donor and neutral acceptor complexes as well as the electron-hole exchange constant for close donor-acceptor pa irs. Both the fine structure of the neutral acceptor-bound exciton emission and the specific properties of donor-acceptor pair spectra observed in mag netoluminescence experiments are tentatively attributed to the internal str ucture of the acceptor state.