SPECTROSCOPIC STUDIES OF HEAVILY CARBON-DOPED GAAS GROWN BY METAL-ORGANIC CHEMICAL-VAPOR EPITAXY

Spectroscopic studies of the minority electron lifetimes and photolumi nescence efficiencies of heavily carbon-doped GaAs are reported. The G aAs layers were grown by metal organic chemical vapor epitaxy (MOVPE) at 650 degrees C with carbon tetrabromide used as a dopant source, Com bined minority electron lifetime and internal quantum efficiency measu rements allowed us to determine the radiative decay times in heavily c arbon-doped GaAs to be longer than that we would expect if a value for the radiative recombination constant of B = 2.0 X 10(-10) cm(3) s(-1) were used. Taking into account the effects of hole-hole and hole-ioni zed impurity scattering, we show that B decreases as hole density incr eases in heavily carbon-doped GaAs. With the use of the revised values for B, the calculated radiative decay times were compatible with our measurements.