CONTACTLESS SPECTROSCOPY OF DEEP LEVELS IN SEMICONDUCTING MATERIALS -GAAS

The surface photovoltage (SPV) and photocurrent (PC) transients as a r esult of the excitation by the short high-intensity light pulses from semiconductor's intrinsic absorption spectral region are investigated in semi-insulating GaAs. It is shown that the mathematical convolution of SPV transients and arbitrary form double-pulse integrator (lock-in , double-boxcar) in a wide temperature range allows to receive the dee p-level (DL) spectrum without the need to form electrical contacts to the crystal investigated. The use of such a procedure while scanning t he crystal surface with a light spot at a temperature, corresponding t o some DL maximum in the spectrum, makes possible the contactless dete rmination of this DL density distribution profile along the scanning d irection.