Buffer-material dependence of InAs quantum dots on GaAs substrate

This letter describes the buffer-material dependence of 1.3-μm-range quantum dots (QDs), a subject that is useful for increasing the dot density while maintaining the photoluminescence (PL) intensity. Four types of buffer material, that is, GaAs, GaAsSb, InGaAs, and Si, were investigated. The PL intensity decreases monotonously with increases in the dot density for all types of buffers. The relationship between the PL intensity and the dot density is almost the same for GaAs, InGaAs, and Si buffer. However, the PL intensity increases about three times when GaAsSb buffer is used. This could be attributed to the reduction of the interfacial defects of the QDs by the surfactant behavior of Sb.