Résumé
For our last research, we concentrated our studies on the quality factor and the room temperature lasing threshold of microdisk cavities. But, electrical injection requires an improved device configuration in order to reduce losses which are intrinsically higher compared to optical pumping. The gain-loss problematic is the key point to achieve and understand the microlaser.Here we investigate and model the temperature dependence of the microlaser operation. The microlaser operate under pulsed optical excitation and laser emission is reached at room temperature around 420 nm. We focus on the spectrum of the spontaneous and stimulated emissions of the InGaN/GaN MQW active layer, which is carefully modelled in order to extract the relevant parameters: carrier concentrations, Fermi levels, effective temperature, etc. We observe the textbook lasing condition, when the gain compensates the resonator losses. An interesting aspect of this study is that for higher powers, the laser effect occurs over the entire gain band. Finally, we show that the typical T0 for these microlasers is elevated (T0=210K), meaning that the temperature dependence around room temperature is reduced. This is due to the thin MBE GaN buffer used to increase the carriers confinement and no leakage in the barriers.