Quantitative analysis of carbon concentration in MOMBE p-GaAs by low-temperature photoluminescence

Several features of low-temperature (2-K) photoluminescence (PL) spectra are used for a quantitative determination of the carbon concentration below 1018 cm−3 in GaAs samples grown by metalorganic molecular-beam epitaxy. We present a close correlation between specific PL features and hole concentration together with a calibration of the carbon content with respect to the hole concentration. This calibration was done directly on samples implanted with a known amount of carbon (1×1016 cm−3) and via local vibrational mode and secondary ion mass spectrometry analysis of samples doped to around 1018 cm−3. The method permits a fast and nondestructive determination of the carbon content from PL measurements.