  Acoustic wave propagation in bulk GaN Semiconductor in the presence of a
slowly changing a.c electric field and a constant electric field has been
studied. Analytical expression for the attenuation (amplification) coefficient
has been obtained. It is shown that the a.c electric field is acting as a
modulator and that the acoustoelectric gain increases to a maximum value and
then fall off as the acoustic wave frequency is increased. Also for a a.c
electric field of 4 x 104 V/CM the acoustoelectric gain remains zero until the
acoustic wave frequency is about 5.8x1012Hz then a resonant amplification peak
appears. If the a.c electric field is increased a second resonant peak accurs
at 8.7x1012Hz. It is therefore suggested that the sample can be used as a
maser.
