Infra-red O-related photoluminescence measurements were made of epilayers which had been grown by means of organometallic vapor-phase epitaxy and had been intentionally doped using dimethylaluminum methoxide. Photoluminescence emissions were detected at 1.08, 0.95, 0.81 and 0.62eV. The centers which were responsible for the emissions at 0.81 and 0.62eV were tentatively suggested to be Al-O-Ga and Al-O-Al, respectively, on the basis of correlations with the layer growth conditions. The growth parameters provided information on the number of nearest-neighbor Al atoms which were associated with O. The Al-O-Ga center that was responsible for the 0.81eV emission was also studied in AlxGa1-xAs layers, with x ranging from 0.05 to 0.9, that had been grown by means of organometallic vapor-phase epitaxy without dimethylaluminum methoxide. The 0.81eV emission was attributed to a transition from the conduction band to the Al-O-Ga center. The center exhibited a lattice relaxation that was associated with a Franck-Condon shift of 0.15eV. The thermal ionization energy of this acceptor was deduced to be located at 0.56eV above the valence band.

P.W.Yu, Y.Park, M.Skowronski, M.L.Timmons: Journal of Applied Physics, 1995, 78[3], 2015-21