Effect of Screening of Piezoelectric Phonon Fields on Absorption-Edge Broadening in GaAs

Abstract
The broadening of the intrinsic absorption edge by intense, acoustoelectrically amplified phonon flux in piezoelectric semiconductors is well established. A definitive test is presented to show that the piezoelectric fields of the phonons in GaAs are predominantly responsible for this effect. The test consists of using intense extrinsic generation of excess electrons by a Q-switched, Nd-doped yttrium-aluminium-garnet laser to screen out the piezoelectric fields without affecting the acoustic intensity.