Excitonic lasing of strain-free InP(As) quantum dots in AllnAs microdisk

摘要

Formation, emission, and lasing properties of strain-free InP(As)/AlInAs quantum dots (QDs) embedded in AllnAs microdisk (MD) cavity were investigated using transmission electron micros-copy and photoluminescence (PL) techniques. In MD structures, the QDs have the nano-pan-cake shape with the height of ~2nm, the lateral size of 20-50 nm, and the density of ~5 x 10~9 cm~(-2). Their emission observed at ~940 nm revealed strong temperature quenching, which points to exci-ton decomposition. It also showed unexpected type-I character, indicating In-As intermixing as confirmed by band structure calculations. We observed lasing of InP(As) QD excitons into whispering gallery modes in MD having the diameter of ~3.2 μm and providing a free spectral range of ~27nm and quality factors up to Q~ 13 000. Threshold of ~50W/cm~2 and spontaneous emission coupling coefficient of ~0.2 were measured for this MD-QD system.