Abstract

We report electrically pumped lasing at room temperature in microresonators 2-5 µm in diameter. The active media were three quantum wells of 80-Å In_0.2Ga_0.8As with 100-Å barriers. The mirrors were GaAs/AlAs quarterwave stacks with 20.5 pairs on the bottom n-doped and 12 pairs, p-doped, on top. Additionally, the top mirror had a fraction of a quarterwave AlAs, 30-Å δ-doped GaAs, and was capped by 1500-Å Au. The semiconductor heterostructure was grown by molecular beam epitaxy, and chemical beam ion-beam assisted etching etched through the Au cap and the >5-µm heterostructure. The substrate backside was polished and grounded while an electrical probe contacted the Au cap. The <2-Å wide 958-nm output was linearly polarized. With 50-ns pulses a 3-µm device had a 1.3-mA threshold with ~15% internal slope efficiency on a linear slope. We attained duty cycles >25%. Resistance was very high, ~10 kΩ due to its small diameter, probe contact, and well/ barrier nature of the mirrors. Use of a single quantum well and surface passivation should reduce thresholds to ~10 µA, making such resistances tolerable and allow cw operation.

© 1989 Optical Society of America