Calibration of the carbon localized vibrational mode absorption line in GaAs

The residual carbon acceptor concentration [CAs] in three radio-tin-doped, liquid encapsulated Czochralski, GaAs single crystals was estimated from a plot of carrier concentration versus tin concentration determined by radio-tracer counting. Local vibrational mode absorption of CAs in the samples was measured at room temperature and a calibration factor of 8±2×1015 cm−1 obtained. A comparison of this with other determinations suggests that the true calibration factor lies between 8 and 11×1015 cm−1 and that earlier, larger calibration factors should be discounted.