Enhanced photoluminescence intensity of buried InGaAs/GaAs(001) quantum wells by sulfur termination

Sulfur (S) termination of III-V semiconductor surfaces is an effective technique for passivating surfaces to prevent oxidation. In this study, we systematically investigated the effects of S termination by (NH4)2Sx treatment on enhancement of the photoluminescence (PL) properties of buried InGaAs/GaAs(001) quantum wells (QWs). X-ray photoelectron spectroscopy (XPS) and PL measurements revealed that the (NH4)2Sx treatment suppresses the formation of surface oxides, especially arsenic oxides, and enhances the PL intensity of QWs. Clear correlation between the PL and XPS results suggests that greater PL intensity is attributable to a reduction in the number of nonradiative recombination centers at the surface caused by arsenic oxide formation. In addition, from the observed temporal changes in PL intensities, we found that the S-terminated surfaces exhibit long-term and high resistance to surface oxidation by air exposure.