Picosecond acoustics in p-doped piezoelectric semiconductors
Résumé
We demonstrate by experiment and theoretical analysis that the presence of built-in electric fields near the (111) and (-1-1-1) surfaces of p-doped GaAs causes efficient generation of acoustic waves due to the laser-induced inverse piezoelectric effect. At the same time, the generation efficiency from the electron-hole-phonon deformation potential is shown to be reduced. The polarity of the acoustic pulse is inverted when changing the laser irradiated surface from (111) to (-1-1-1). The results have ramifications for optically controlled piezoelectric ultrasound transducers.