InP self-assembled quantum dots embedded in In/sub 0.5/Al/sub 0.3/Ga/sub 0.2/P grown on GaAs substrates by metalorganic chemical vapor deposition

Abstract

We report the characteristics of InP self-assembled quantum dots embedded in In/sub 0.5/Al/sub 0.3/Ga/sub 0.2/P on GaAs substrates. InP quantum dots are grown at 650/spl deg/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 /spl sim/10 dots/cm/sup 2/. 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/sub 0.5/Al/sub 0.3/Ga/sub 0.2/P/In/sub 0.49/Al/sub 0.51/P quantum dot heterostructures exhibit stimulated emission at room temperature and laser operation at /spl sim/680 nm.