arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1206.0280cond-mat.mes-hall
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硅基太赫兹量子级联激光器的扩展密度矩阵模型

An extended density matrix model applied to silicon-based terahertz quantum cascade lasers

T. V. Dinh, A. Valavanis, L. J. M. Lever, Z. Ikonić, R. W. Kelsall

摘要:

硅基太赫兹量子级联激光器(QCL)提供了优于现有III-V族器件的潜在优势。尽管已知相干电子输运效应在QCL中很重要,但在Si基器件设计中从未考虑过它们。我们描述了一个密度矩阵传输模型,该模型被设计成比以前的研究中的那些更一般,并需要较少的先验知识的电子能带结构,允许其使用在半自动化的设计程序。该模型的基础包括所有的状态,在周期间运输,我们的稳态解决方案扩展到超越的行波近似,包括DC和反向传播条款。我们模拟了束缚到连续Ge/SiGe QCL的潜在性能,发现具有4-5 nm厚势垒的器件具有最高的模拟光学增益。我们还研究了Ge和SiGe层之间的相互扩散的影响,我们表明,如果它是考虑到在设计中,相互扩散长度高达1.5 nm不会显着影响模拟器件的性能。

英文摘要:

Silicon-based terahertz quantum cascade lasers (QCLs) offer potential advantages over existing III-V devices. Although coherent electron transport effects are known to be important in QCLs, they have never been considered in Si-based device designs. We describe a density matrix transport model that is designed to be more general than those in previous studies and to require less a priori knowlege of electronic bandstructure, allowing its use in semi-automated design procedures. The basis of the model includes all states involved in interperiod transport, and our steady-state solution extends beyond the rotating-wave approximation by including DC and counter-propagating terms. We simulate the potential performance of bound-to-continuum Ge/SiGe QCLs and find that devices with 4-5-nm-thick barriers give the highest simulated optical gain. We also examine the effects of interdiffusion between Ge and SiGe layers; we show that if it is taken into account in the design, interdiffusion lengths of up to 1.5 nm do not significantly affect the simulated device performance.

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