半导体太赫兹源综述

太赫兹技术可以应用于信息科学，生物，医学，天文和环境科学等方面，而太赫兹源是太赫兹应用的关键器件。作者针对半导体太赫兹源如GaAs1-xNx二极管、量子阱负有效质量太赫兹振荡器和太赫兹量子级联激光器做了一个简要的回顾。掺杂的GaAs1-xNx二极管在直流偏压下的电流自振荡行为得到了研究，发现电流自振荡与这种独特材料体系非抛物线型导带的负微分速率效应相关。量子阱负有效质量p pp 二极管通过考虑杂质散射、光学声子和声学声子散射研究了其电流自振荡和瞬时电流形态，研究发现偏压和掺杂浓度会对电流自振荡频率产生很大影响，负有效质量p pp 二极管可以用作可电学调制的太赫兹源。此外，我们通过蒙特卡洛模拟对共振声子结构的太赫兹量子级联激光器进行了器件参数的优化，结果表明注入势垒宽度、掺杂浓度和声子抽取能级差设计对计算增益有很大的影响，我们的计算结果与实验结果一致。

Review of terahertz semiconductor sources

Terahertz (THz) technology can be used in information science, biology, medicine, astronomy, and environmental science. THz sources are the key devices in THz applications. The author gives a brief review of THz semiconductor sources, such as GaAs_1-xN_x Gunn-like diodes, quantum wells (QWs) negative-effective-mass (NEM) THz oscillators, and the THz quantum cascade lasers (QCLs). THz current self-oscillation in doped GaAs_1-xN_x diodes driven by a DC electric field was investigated. The current self-oscillation is associated with the negative differential velocity effect in the highly nonparabolic conduction band of this unique material system. The current self-oscillations and spatiotemporal current patterns in QW NEM p⁺pp⁺ diodes was studied by considering scattering contributions from impurities, acoustic phonons, and optic phonons. It is indicated that both the applied bias and the doping concentration strongly influence the patterns and self-oscillating frequencies. The NEM p⁺pp⁺ diode may be used as an electrically tunable THz source. Meanwhile, by using the Monte Carlo method, the device parameters of resonant-phonon THz QCLs were optimized. The results show that the calculated gain is more sensitive to the injection barrier width, the doping concentration, and the phonon extraction level separation, which is consistent with the experiments.