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We report on resonant photoluminescence ͑PL͒ of InGaN inclusions in a GaN matrix. The structures were grown on sapphire substrates using metal-organic chemical vapor deposition. Nonresonant pulsed excitation results in a broad PL peak, while resonant excitation into the nonresonant PL intensity maximum results in an evolution of a sharp resonant PL peak, having a spectral shape defined by the excitation laser pulse and a radiative decay time close to that revealed for PL under nonresonant excitation. Observation of a resonantly excited narrow PL line gives clear proof of the quantum dot nature of luminescence in InGaN-GaN samples. PL decay demonstrates strongly nonexponential behavior evidencing coexistence of quantum dots having similar ground-state transition energy, but very different electron-hole wave-function overlap.

We report photopumped room-temperature surface-mode lasing at 401 nm in a InGaAlN vertical-cavity surface-emitting laser grown on a sapphire substrate using metal–organic vapor-phase epitaxy. A 2λ cavity was formed by a quarter-wave Al0.15Ga0.85N/GaN distributed Bragg reflector on the one side of the active layer and a GaN–air interface on the other. A multilayer structure composed of 12-fold-stacked ultrathin InGaN insertions in a GaN matrix served as an active layer providing ultrahigh material gain and making possible vertical lasing without use of the upper Bragg reflector.