Si delta doping inside InAs/GaAs quantum dots with different doping densities

Abstract

During the growth process of InAs/GaAs self-assembled quantum dots (QDs), Si delta doping with different doping densities was carried out during initial QD formation. Atomic force microscopy (AFM) reveals that this Si doping affects the QD morphology only slightly. Conductive AFM measurements show that the current on the surface QDs increases at low doping densities, but decreases unexpectedly at high doping densities. Temperature-dependent photoluminescence (PL) measurements show that an optimized Si doping density (5 × 1011 cm−2) improves the PL thermal stability for an intermediate temperature range from 125 to 225 K and enhances the PL intensity up to 35 times at room temperature. These results indicate that the Si doping density plays a key role in the electrical and optical properties of InAs QDs.