PHOTOLUMINESCENCE FROM WURTZITE GAN UNDER HYDROSTATIC-PRESSURE

The photoluminescence spectrum of undoped epitaxial wurtzite GaN layer s on sapphire was measured for applied hydrostatic pressures up to 73 kbar at 9 K and up to 62 kbar at 300 K. The pressure dependences of th e I-2 exciton recombination line and the ''yellow'' band (2.2 eV band at ambient pressure) were examined at 9 and 300 K, and the series of d onor-acceptor-pair emission lines was analyzed at 9 K. From the I-2 li nes, it was found that the band gap increases with pressure by 4.4+/-0 .1 meV/kbar at 9 K and 4.7+/-0.1 meV/kbar at 300 K. (C) 1995 American Institute of Physics.