Highly Uniform and Small InP/GaInP Self-Assembled Quantum Dots Grown by Metal-Organic Vapor Phase Epitaxy

Abstract

InP self-assembled quantum dots embedded in Ga0.51In0.49P were prepared by metal-organic vapor phase epitaxy. In order to reduce the dot diameter and improve the size uniformity, InP dots were grown at a low temperature using tertiarybutyl-phosphine instead of phosphine. Growth of 4 ML InP on a 4 ML GaP interface layer at 550°C resulted in InP islands of about 30 nm in base diameter and 7 nm in height that were remarkably uniform to within 10% deviation. The insertion of another 2 ML GaP interface layer between the InP islands and the GaInP cap-layer further reduced the half-width of the photoluminescence (PL) spectra from the InP dots to 29 meV at both 2 K and 77 K. It is necessary to grow the GaInP caplayer at higher than 630°C in order to alloy the undeveloped InP clusters and wetting layer with GaP interface layers.