InP self-assembled quantum dots embedded in In0.5Al0.3Ga0.2P grown on GaAs substrates by metalorganic chemical vapor deposition

We report the characteristics of InP self-assembled quantum dots embedded in In_0.5Al_0.3Ga_0.2P on GaAs substrates. InP quantum dots are grown at 650°C for various deposition times via the Stranski-Krastanow growth mode by metalorganic chemical vapor deposition. Atomic force microscopy and transmission electron microscopy show the formation of densely distributed coherent quantum dots. The InP quantum dots grown for up to “planar-layer-growth equivalent” 15 MLs have dominant sizes of 5-20 nm (height) and a density of ~10 dots/cm². These InP quantum dots have broad range of luminescence corresponding to red or orange in the visible spectrum, depending on growth times. As the deposition time increases, the photoluminescence peak shifts toward the lower energy side, due to an increase in the dominant size of the quantum dots. Also, optical pumping is performed on double-stacked InP quantum dot layers. In addition, InP/In_0.5Al_0.3Ga _0.2P/In_0.49Al_0.51P quantum dot heterostructures exhibit stimulated emission at room temperature and laser operation at ~680 nm