  Formation, emission and lasing properties of strain-free InP(As)/AlInAs
quantum dots (QDs) embedded in AlInAs microdisk (MD) cavity were investigated
using transmission electron microscopy and photoluminescence (PL) techniques.
In MD structures, the QDs having nano-pan-cake shape have height of ~2 nm,
lateral size of 20-50 nm and density of ~5x109 cm-2. Their emission observed at
~940 nm revealed strong temperature quenching, which points to exciton
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 dimeter ~3.2 mkm
and providing free spectral range of ~27 nm and quality factors up to Q~13000.
Threshold of ~50 W/cm2 and spontaneous emission coupling coefficient of ~0.2
were measured for this MD-QD system.
