Optimization of terahertz quantum cascade lasers by suppressing carrier leakage channel via high-energy state
Optimization of terahertz quantum cascade lasers by suppressing carrier leakage channel via high-energy state
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DOI：
10.7567/apex.11.112702
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发表时间：
2018-10
影响因子：
2.3
通讯作者：
Tsung-Tse Lin;Li Wang;Ke Wang;T. Grange;H. Hirayama
中科院分区：
文献类型：
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作者：
Tsung-Tse Lin;Li Wang;Ke Wang;T. Grange;H. Hirayama
用非平衡态格林函数方法对太赫兹量子级联激光器进行了理论分析。模拟结果表明，在下一个周期的发射双势垒中，存在从上激光能级到第一高能态的载流子泄漏通道。该泄漏通道是由于两个状态的无意对齐，并且不同于热激活的泄漏通道。通过调节这种高能态的能量，明显地抑制了泄漏电流。与优化前的220 mW相比，优化后的THzQCL的峰值功率达到350 mW，有了显著的改善。
Terahertz quantum cascade lasers (THz QCLs) are theoretically analyzed using the non-equilibrium Green’s function method. Simulations reveal a carrier leakage channel from the upper laser level to the first high-energy state in the emitting double well of the next period. This leakage channel is due to unintentional alignment of the two states, and is distinct from the thermally activated leakage channels. By tuning the energy of this high-energy state, the leakage current is clearly suppressed. The optimized THz QCL shows significant improvement, with a peak power of 350 mW, compared with the value of 220 mW for the non-optimized structure.