Resonant tunneling in quantum cascade lasers
Resonant tunneling in quantum cascade lasers
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DOI：
10.1109/3.709589
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发表时间：
1998-09-01
影响因子：
2.5
通讯作者：
Cho, AY
中科院分区：
文献类型：
--
作者：
Sirtori, C;Capasso, F;Cho, AY
讨论了在量子级联激光器中电子注入有源区是由二维子带之间的谐振隧道控制的实验证据。使用基于紧束缚近似的电流密度方程进行定量分析，当电流密度受到激光跃迁激发态寿命的限制时，优化电子注入有源区。在这种状态下，注入器基态的布居和激光跃迁的激发态的布居之间达到准平衡，其特征在于共同的准费米能级。注入器的设计取决于所选的激光活性区域；特别是，物理参数的选择，例如掺杂浓度和注入势垒厚度，对于垂直或对角跃迁激光器来说通常是不同的。本文最后研究了阈值传输特性及其对受激发射的依赖性；推导出阈值以上的微分电阻与斜率效率值之间的关系。
Experimental evidence that in quantum cascade lasers electron injection into the active region is controlled by resonant tunneling between two-dimensional subbands is discussed. A quantitative analysis is carried out using an equation for the current density based on a tight-binding approximation, Electron injection into the active region is optimized when the current density is limited by the lifetime of the excited state of the laser transition. In this regime, quasi-equilibrium is reached between the population of the injector ground state and that of the excited state of the laser transition characterized by a common quasi-Fermi level. The design of the injector depends on the selected laser active region; in particular, the choice of physical parameters, such as doping concentration and injection barrier thicknesses, is in general different for vertical or diagonal transition lasers, The paper concludes with an investigation of the transport properties at threshold and its dependence on stimulated emission; a relationship between the differential resistance above threshold and the value of the slope efficiency is deduced.