Nondestructive Photoacoustic Measurement of Doping Densities in Bulk GaAs

The frequency-dependent photoacoustic (PA) signals and phase spectra of GaAs samples with different doping densities are measured and analyzed. In particular, we find that the magnitude differences of the PA signal and phase between intrinsic GaAs and doped GaAs materials decrease linearly with the doping density in the frequency region of nonradiative bulk recombination. The results show that the PA spectroscopic technique can be used to measure doping density in bulk semiconductors with reasonable accuracy.