Hou Yufei, Zhao Degang, Chen Ping, Liang Feng, Liu Zongshun, Yang Jing
Opt Express. 2021 Oct 11;29(21):33992-34001. doi: 10.1364/OE.435062.
We propose a stepped upper waveguide layer (UWG) to improve the hole injection efficiency of GaN-based laser diodes (LDs), and investigate its effect on the performance of LDs from experiments and theoretical calculations. The experimental characterization of the LD with stepped UWG presents a decrease of 16.6% for the threshold current as well as an increase of 41.2% for the slope efficiency compared to the LD with conventional GaN UWG. Meanwhile, strong localized effects are found in the quantum wells of LD with stepped UWG and a large blue-shift in the electroluminescence (EL) spectra below the threshold by analyzing the differential efficiency and the EL spectra. The large blue shift implies a stronger polarization field in the LDs, which may affect the injection of holes. Additionally, the simulation results demonstrate that the LD with stepped UWG achieves higher hole injection efficiency by modulating the valence band, and the hole current density injected into the quantum wells reaches 6067 A/cm.
我们提出一种阶梯状上波导层（UWG）来提高基于氮化镓的激光二极管（LDs）的空穴注入效率，并通过实验和理论计算研究其对LDs性能的影响。与具有传统氮化镓UWG的LD相比，具有阶梯状UWG的LD的实验表征显示阈值电流降低了16.6%，斜率效率提高了41.2%。同时，通过分析微分效率和电致发光（EL）光谱，发现在具有阶梯状UWG的LD的量子阱中存在强烈的局域效应，并且在阈值以下的EL光谱中出现了大的蓝移。大的蓝移意味着LDs中存在更强的极化场，这可能会影响空穴的注入。此外，模拟结果表明，具有阶梯状UWG的LD通过调制价带实现了更高空穴注入效率，注入到量子阱中的空穴电流密度达到6067 A/cm² 。
