Photopumped red-emitting InP/In_0.5Al_0.3Ga_0.2P self-assembled quantum dot heterostructure lasers grown by metalorganic chemical vapor deposition

Abstract

We report the 300 K operation of optically pumped red-emitting lasers fabricated from InP self-assembled quantum dots embedded in In_0.5Al_0.3Ga_0.2P layers on GaAs (100) substrates grown by metalorganic chemical vapor deposition. Quantum dots grown at 650° C on In_0.5Al_0.3Ga_0.2P layers have a high density on the order of 10¹⁰ cm^-2 and the dominant size of individual quantum dots ranges from -5 to -10 nm for 7.5 monolayer "equivalent growth." These InP/In_0.5Al_0.3Ga_0.2P quantum dot heterostructures are characterized by atomic force microscopy, high-resolution transmission electron microscopy, and photoluminescence. Laser structures are prepared from wafers having two vertically stacked InP quantum dot active layers within a 100-nm-thick In_0.5Al_0.3Ga_0.2P waveguide and upper and lower 600 nm InAlP cladding layers. We observe lasing at λ-680 nm at room temperature in optically pumped samples.