Influence of doping profiles on coherent acoustic phonon detection and generation in semiconductors

A laser based picosecond ultrasound technique is used to study the doping profile in different n-doped GaAs homoepitaxial structures grown by molecular beam epitaxy. The picosecond ultrasound is found to be good tool to detect doping profile with doping densities of the order of [10.sup.18] [cm.sup.-3] based on a different sensitivity function for coherent strain pulse in the doped and undoped regions.