We report on memory effects in the optical properties of GaN and AIN e
pitaxial-films grown by atmospheric pressure metal organic chemical va
por deposition. After exposing selected areas of particular samples wi
th He-Cd laser light (3.8 eV), we observed a persistent and marked dec
rease in the near band edge photoluminescence (PL) intensity emitted f
rom these areas. This effect has been observed in epitaxial films that
typically have a pyramidlike hillock surface. This ability to modulat
e PL emission intensity at individual points in these materials can be
exploited as a method for optical data storage. A means of erasing in
formation stored using this effect has also been investigated using lo
wer energy (similar to 2 eV). (C) 1997 American Institute of Physics.