InGaAsN/GaAs quantum-well-based microlasers improved by PECVD SiO₂ passivation

The influence of cavity surface passivation with SiO₂ coating deposited by the plasma-enhanced chemical vapor deposition technique is investigated for injection microdisk lasers with an InGaAsN/GaAs quantum well active region. The electroluminescence spectra of the microdisk lasers with cavity diameters ranging from 12 to 32 μm with and without sidewall surface passivation were studied for a wide range of injection currents. It is shown that surface passivation with silicon dioxide reduces threshold currents by a factor of 2-5 compared to non-passivated microlasers. Temperature stability of passivated microlaser operation is also investigated up to 90°C. The results achieved show that PECVD SiO₂ passivation is an effective yet easy-to-implement method for improving the threshold characteristics applicable to InGaAsN-based microdisk laser resonators.