Recognition of non-radiative recombination centres in semi-insulating GaAs

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Abstract
A novel technique, double-beam photoluminescence (DBPL), is introduced. This is used to investigate photoquenching effects of deep levels which affect near-band-edge photoluminescence (PL) in bulk-grown semi-insulating (SI) GaAs. The authors show that there is a remarkable increase in band-to-band radiative transition efficiency after photoquenching of near-band-edge absorption (also known as Reverse Contrast or RC) at low temperatures (less than 35 K) and suggest that RC absorption does indeed map concentrations of the dominant associate this effect with a reduction in non-radiative recombination centres. They suggest that RC absorption does indeed map concentrations of the dominant recombination centre in SI GaAs and that the observed increase in luminescence after low-temperature illumination with light of near 1 mu m wavelength is due to photoquenching of the RC defects.