Raman spectroscopic study of point defects in bulk GaAs.

Raman scattering with below-band-gap light has been used to study residual extrinsic acceptors as well as the intrinsic 78/203 meV double acceptor in bulk GaAs. Both electronic and vibronic excitations of these defects are observed in the low-temperature Raman spectrum. Electronic scattering of extrinsic acceptors - namely carbon and zinc - in semi-insulating material provides a quantitative tool for materials characterization with a detection limit of smaller than 5x10 E14 acceptors/cubic meter. Polarized Raman spectra give insight into the electronic structure of the 78/203 meV acceptor. (IAF)