The Red (1.8 eV) Luminescence in Epitaxially Grown GaN

The 1.8 eV luminescence band in GaN grown by molecular beam epitaxy is studied by photo-luminescence (PL) and magnetic resonance. Optically detected magnetic resonance (ODMR) shows that deep centres with g = 1.98 and g = 2.01 are involved in the recombination. The results of the PL experiments indicate that the 1.8 eV recombination can be further fed by shallow centres like shallow donors or excitons.