DETERMINATION OF THE CHARGE CARRIER CONCENTRATION ACROSS GROWTH STRIATIONS IN N-GAAS BY RAMAN-SPECTROSCOPY

Using a Raman microprobe, the charge carrier concentration across growth striations in Bridgman n-GaAs is determined both by the analysis of coupled LO-phonon-plasmon modes and their relative intensities compared to that of the uncoupled LO phonon of the depletion layer. It is shown that the charge carrier concentration typically varies by +/- 10% in the regions both under rough and facetting growth conditions. In the facetting growth region the charge carrier concentration appears to be higher by about 50%.