Current-injection operation of quantum-wire lasers and verification of low threshold currents

通过垂直和平行的p和n掺杂层的电流注入，实现了两种T型量子线(T线)激光器的单模激光。该激光器的腔长为0.5 mm，腔面镀覆了高反射率的Au/SiO_2薄膜。T型线激光器是用解理边缘覆盖法形成的，激光光波导位于每个晶片的一角，这是我们不能使用传统的光刻技术来实现的。此外，具有非平坦结构的T线激光器的奇异p-n结几何结构不能用传统的一维泊松方程工具来设计。因此，我们通过试错法设计了T线激光器中垂直和平行的掺杂分布，开发了手工半导体加工方法，并设计了我们自己的光学表征工具110K以上，这是电流注入T线激光器中的最高激光温度。当温度为100K时，激光器性能最佳，阈值电流为2.1 mA，微分量子效率为0.9%。另一方面，在具有20个T线阵列和平行的p和n掺杂层的T线激光器中，我们在30-70K的温度范围内观察到了单模激光。当温度为30K时，激光器性能达到最佳，阈值电流最低为0.27 mA，最高微分量子效率为12%。0.27 mA的阈值电流相当于每根T线14μA。用Yariv的分析方法估算的理论值为：线长为0.5 mm，温度为30K，载流子寿命为0.4 ns时，每根T线的电流约为10μA。我们目前的结果与这一估计非常接近，并在原则上证实了量子线激光器的低阈值电流预测。对我们的电流注入T线激光器的发光和激光光谱、电流-电压特性、电流-光输出特性、阈值电流、微分量子效率以及它们的温度依赖关系进行了进一步的详细表征。较少

We achieved single-mode lasing in two-types of T-shaped-quantum-wire (T-wire) lasers using current-injection via perpendicular and parallel p-and n-doping layers. These lasers had cavity length of 0.5 mm and cavity mirror facets coated by high-reflectivity Au/SiO2 thin films. The T-wire lasers are formed by the cleaved-edge overgrowth method, and laser optical waveguide is located at a corner on each wafer, for which we cannot use conventional photo-lithography technique. In addition, singular p-n junction geometry of T-wire lasers with non-plainer structures cannot be designed with conventional one-dimensional Poisson equation tools. Therefore, we designed perpendicular and parallel doping profiles in T-wire lasers by try-and-errors, developed manual semiconductor processing methods, and devised our homemade optical characterization tools.In a T-wire laser with 15-array of T-wires and perpendicular p-and n-doping layers, we observed single-mode lasing in a wide temperature range of 5- … More 110K, which is the highest lasing temperature in current-injection T-wire lasers. Laser performance becomes optimum at 100 K, where we obtained threshold current of 2.1mA and differential quantum efficiency of 0.9%. In a T-wire laser with 20-array of T-wires and parallel p-and n-doping layers, on the other hand, we observed single-mode lasing in a temperature range of 30-70K. Laser performance becomes optimum at 30 K, where we obtained the lowest threshold current of 0.27 mA and high differential quantum efficiency of 12%. This threshold current value of 0.27 mA corresponds to 14 μ A per single T-wire. A theoretical value estimated by Yariv's analysis method and wire length of 0.5 mm, temperature of 30 K, and carrier lifetime of 0.4 ns is about 10 μ A per single T-wire. Our present result is very close to this estimation, and in principle confirms the predicted low threshold current in quantum wire lasers. Further detailed characterizations of luminescence and lasing spectra, current-voltage characteristics, current-light-output characteristics, threshold currents, differential quantum efficiencies as well as their temperature dependences have been achieved on our current-injection T-wire lasers. Less