NEAR-BAND-EDGE PHOTOLUMINESCENCE EMISSION IN ALXGA1-XN UNDER HIGH-PRESSURE

We present results of pressure-dependent photoluminescence (PL) studie s of single-crystal AlxGa1-xN epitaxial films grown on sapphire substr ates by metalorganic chemical vapor deposition. PL measurements were p erformed under hydrostatic pressure using the diamond-anvil-cell techn ique. PL spectra taken from the AlxGa1-xN epitaxial films are dominate d by strong near-band-edge luminescence emissions. The emission lines were found to shift linearly towards higher energy with increasing pre ssure. By examining the pressure dependence of the spectral features, the pressure coefficients for the PL emissions associated with the dir ect Gamma band gap of AlxGa1-xN were determined. Our results yield a p ressure coefficient of 4.0x10(-3) eV/kbar for Al0.05Ga0.95N and 3.6x10 (-3) eV/kbar for Al0.35Ga0.65N. (C) 1998 American Institute of Physics .