Photopumped red-emitting InP/In0.5Al0.3Ga0.2P self-assembled quantum dot heterostructure lasers grown by metalorganic chemical vapor deposition

We report the 300 K operation of optically pumped red-emitting lasers fabricated from InP self-assembled quantum dots embedded in ${\mathrm{In}}_{\mathrm{0.5}}{\mathrm{Al}}_{\mathrm{0.3}}{\mathrm{Ga}}_{\mathrm{0.2}}\mathrm{P}$ layers on GaAs (100) substrates grown by metalorganic chemical vapor deposition. Quantum dots grown at 650 °C on ${\mathrm{In}}_{\mathrm{0.5}}{\mathrm{Al}}_{\mathrm{0.3}}{\mathrm{Ga}}_{\mathrm{0.2}}\mathrm{P}$ layers have a high density on the order of ${10}^{10}$ ${\mathrm{cm}}^{\mathrm{-2}}$ and the dominant size of individual quantum dots ranges from ∼5 to ∼10 nm for 7.5 monolayer “equivalent growth.” These ${\mathrm{InP/In}}_{\mathrm{0.5}}{\mathrm{Al}}_{\mathrm{0.3}}{\mathrm{Ga}}_{\mathrm{0.2}}\mathrm{P}$ 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 ${\mathrm{In}}_{\mathrm{0.5}}{\mathrm{Al}}_{\mathrm{0.3}}{\mathrm{Ga}}_{\mathrm{0.2}}\mathrm{P}$ waveguide and upper and lower 600 nm InAlP cladding layers. We observe lasing at λ∼680 nm at room temperature in optically pumped samples.