Evaluation of the impact of surface recombination in microdisk lasers by means of high-frequency modulation

Microdisk lasers 10–30 $\mu$m in diameter operating at room temperature without thermal stabilization and with an active region based on nanostructures of hybrid dimensionality–quantum wells–dots–are investigated. High-frequency measurements of the microlaser response are performed in the direct small-signal modulation mode, which makes it possible to establish the parameters of the operating speed and analyze their dependence on the microlaser diameter. It is found that the K factor is (0.8 $\pm$ 0.2) ns, which corresponds to optical losses of $\sim$6 cm$^{-1}$, and no regular dependence on the diameter is observed. It is found that the low-frequency component of the damping coefficient of relaxation oscillations is inversely proportional to the diameter. This character of the dependence evidences a decrease in the carrier lifetime in small-diameter microcavities, which can be associated with the prevalence of nonradiative recombination on their side walls.