The role of electron temperature in the leakage current in QCLs and its impact on the quantum efficiency
The role of electron temperature in the leakage current in QCLs and its impact on the quantum efficiency
复制标题
电子温度在 QCL 漏电流中的作用及其对量子效率的影响
DOI：
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
W. Masselink
中科院分区：
文献类型：
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作者：
Y. Flores;S. Kurlov;M. Elagin;M. Semtsiv;W. Masselink
最近，我们描述了一种方法来分析泄漏电流（Jleak）的量子级联激光器（QCL）的载流子散射到更高的迷你带由于LO声子吸收。在他的演讲中，我们分析Jleak由于弹性散射。我们说明如何在低温下，当非弹性散射是可以忽略不计的，这个电流变得显着的设备在高电子温度下工作。测量阈值以上的Jleak，我们能够研究电子温度对微分量子效率的影响。这个过程是由一个自洽的计算的速率方程的基础上的唯象散射率模型。我们应用我们的方法，测量了在低占空比和80 K的热沉温度下，发射近5.4 μm的QCL的阈值以上的Jleak作为电子温度的函数。然后使用基于子带间界面粗糙度散射的热激活、电子温度驱动的散射模型对该电流进行建模。结果，由于电子温度的增加，估计上激光态粒子数减少了约35%。当电子温度为400 K时，量子效率降低约80%。
We have recently described a method to analyze the leakage current (Jleak) in quantum-cascade lasers (QCLs) for carriers scattering into higher minibands due to LO-phonon absorption. In his presentation we analyze Jleak due to elastic scattering. We illustrate how at low temperature, when inelastic scattering is negligible, this current becomes significant for devices operating at high electron temperatures. Measuring Jleak above threshold we are able to investigate the effect of electron temperature on the differential quantum efficiency. This procedure is supported by a self-consistent calculation of the rate equations based on a phenomenological scattering-rate model. We apply our approach and measure Jleak above threshold as a function of electron temperature for a QCL emitting near 5.4 μm operated at a low duty cycle and a heat sink temperature of 80 K. This current is then modeled using a thermally activated, electron temperature-driven, scattering model based on intersubband interface roughness scattering. As a result, a reduction in the upper laser state population by ∼35% is estimated due to the effect of increased electron temperature. A decrease of the quantum efficiency of ∼80% is estimated for an electron temperature of 400 K.