MOCVD Growth and Optical Characterization of Strain-Induced Quantum Dots with InP Island Stressors

Coherent InP islands, grown by low pressure metal organic chemical vapor deposition (MOCVD), were used to produce quantum dots by strain confinement. Lateral confinement of carriers in a GaAs/AlGaAs quantum well located near the surface was obtained from the inhomogeneous strain produced by the InP islands. The evolution of the InP islands on A1_0.3Ga_0.7As surfaces with increasing InP coverage at different growth temperatures and substrate orientations was studied using atomic force microscopy. Under certain growth conditions, a fairly uniform distribution of coherent InP islands was obtained which had an average apparent diameter of 140 nm with a standard deviation of 12.2 nm and height of 19.5 ± 1.1 nm. Lateral confinement depths up to 100 meV were obtained when using the islands as stressors. Photoluminescence from ensembles of the strain-induced dots exhibit multiple peaks, narrow line widths (16 meV) and high efficiency up to room temperature.