Si/SiGe量子级联激光器研究进展

Si／SiGe量子级联激光器是一种新型的带内跃迁的红外光源，突破了Si基材料间接带隙特性对光跃迁的限制。Si/SiGe量子级联激光器的开发将为实现太赫兹有源器件的硅基集成产生深远影响。文章介绍了Si/SiGe量子级联激光器的工作原理，以及这类激光器在能带设计、材料生长和波导制作方面的最新进展。     

Si/SiGe量子级联激光器研究进展

Si/SiGe量子级联激光器是一种新型的带内跃迁的红外光源,突破了Si基材料间接带隙特性对光跃迁的限制.Si/SiGe量子级联激光器的开发将为实现太赫兹有源器件的硅基集成产生深远影响.文章介绍了Si/SiGe量子级联激光器的工作原理,以及这类激光器在能带设计、材料生长和波导制作方面的最新进展.     

量子阱级联激光器

介绍了一种新型的工作于４．２５μｍ的半导体激光器－量子阱级联激光器，这种新型激光器是单极性的，它发光仅依赖于电子而并非正负两种电荷，介绍了这种激光器的结构，工作原理和激光特性。     

Al组分对AlGaN/GaN量子级联激光器性能的影响

通过对激光器一个周期单元的一维薛定谔方程与泊松方程进行自洽求解,得到了能带与电子波函数的分布情况,并且计算了在近共振条件下偶极跃迁元与垒层Al组分的关系,得到了Al组分的优化结果。结果表明,垒层材料的Al组分大约等于0.15时激光器的偶极跃迁元最大,此时激光器处于垂直跃迁工作状态。     

SiGe/Si多量子阱中的光致子带间吸收研究

本文论述了硅锗量子阱中的光致子带间吸收的机理,并在实验中探测SiGe/Si量子阱价带间的红外光致吸收.载流子由氩离子激光器作为光泵浦源产生,所导致的红外吸收由一个步进式傅里叶变换光谱仪来探测.在硅锗量子阱中的光致吸收有两个来源:类似单一掺杂的SiGe薄层的体吸收的自由载流子吸收,及量子阱价带的子带间吸收.实验探测了TE和TM偏振方向的吸收.TM偏振方向的吸收是由偏离布里渊带中心的载流子的跃迁所造成的.我们认为这种光致吸收技术在研究价带耦合效应及其对子带间吸收的影响是非常有效的.     

量子级联激光器有源核中界面声子的特性研究

研究了量子级联激光器有源核中界面声子的色散关系和静电势分布. 根据有源核内部的平移不变性导出了界面声子的色散关系. 计算显示有源核中的界面声子可以分为体声子和表面声子模式. 体声子的色散曲线构成一系列准连续的声子子带，其静电势分布于整个有源核并呈现出Bloch波的特征. 表面声子的色散曲线位于各体声子子带的带隙内，其静电势局域在有源核一侧. 这些结果将有助于量子级联激光器和子带跃迁激光器的优化设计.     

约外量子级联激光器

量子级联激光器是一种基于子带间电子跃迁的新型单极光源,文章系统地介绍了量子级联激光器全新的工作原理,结构设计思想以及它所固有的特点,对其研究现状进行了简略总结,同时对其未来的发展作出展望。     

2.5 THz量子级联激光器的研制

基于束缚态到连续态跃迁有源区能带结构,实现了2.5 THz量子级联激光器的连续波工作。激光器的输出频率随电流可在2.45~2.47 THz之间可调,在连续波工作模式下的最高输出功率大于6.0 mW,最高连续波工作温度为60 K,阈值电流密度为120 A/cm2,经Si透镜整形后的输出光斑为高斯分布。     

InGaAs/GaAs量子点阵列中的能级计算

根据八带k·p理论，在三维InGaAs/GaAs量子点阵列中求解k_x=k_y=k_z=0处的有效质量哈密顿H₀的本征值，得到InGaAs量子点中导带中电子基态E_C1，第一激发态E_C2和重空穴态E_{HH1关键词： InGaAs 量子点 带内跃迁 k·p理论')" href="#">八带k·p理论}     

太赫兹量子级联激光器研究进展

太赫兹技术涉及电磁学、光电子学、半导体物理学、材料科学以及微加工技术等多个学科，它在信息科学、生物学、医学、天文学、环境科学等领域有重要的应用价值．太赫兹辐射源是太赫兹频段应用的关键器件．本文简要介绍了太赫兹电磁波的研究背景、重要特点以及潜在应用，重点讨论了太赫兹半导体量子级联激光器的工作原理和研究进展等．     

Electroluminescence from Si/SiGe quantum cascade emitters

Intersubband electroluminescence results are presented from Si/SiGe quantum cascade emitters at 3.2 THz and at temperatures up to 150 K. The effect of adding doping into the active quantum wells was studied in addition to reduced barrier widths from previous measurements. While the current through the sample is increased by the addition of doping, the emitted power is reduced through additional free carrier absorption and Coulombic scattering. Free electron laser measurements confirm the intersubband transitions in the quantum wells of the cascade devices and produce non-radiative lifetimes of 20 ps between 4 and 150 K.     

Microcavity THz quantum cascade laser

We report operation of disk and ring shaped terahertz (THz) quantum-cascade lasers (QCLs) emitting in the THz region between 3.0 and 3.4 THz. The GaAs/Al_0.15Ga_0.85As heterostructure is based on longitudinal-optical phonon scattering for depopulation of the lower radiative state. A double metal waveguide is used to confine the whispering gallery modes in the gain medium. The threshold current density is at 5 K. 3D Finite-Difference Time-Domain (FDTD) simulations were performed to obtain the field distributions within a THz QCl resonator at different frequencies.     

The progress towards terahertz quantum cascade lasers on silicon substrates

A review is presented of work over the last 10 years which has been aimed at trying to produce a Si‐based THz quantum cascade laser. Potential THz applications and present THz sources will be briefly discussed before the materials issues with the Si/SiGe system is discussed. Waveguide designs and waveguide losses will be presented. Experimental measurements of the non‐radiative lifetimes for intersubband transitions in Si_1‐xGe_x quantum wells will be presented along with theory explaining the important scattering mechanisms which determine the lifetimes. Examples of p‐type Si/SiGe quantum cascade designs with the experimental electroluminescence will be reviewed and examples of n‐type Si‐based designs will be presented. In the conclusion designs and structures will be discussed with the greatest potential to achieve an electrically pumped Si‐based THz laser.     

Study of valence intersubband absorption in tensile strained Si/SiGe quantum wells

The hole subband structures and effective masses of tensile strained Si/Sil-yGey quantum wells are calculated by using the 6 × 6 k·p method. The results show that when the tensile strain is induced in the quantum well, the light-hole state becomes the ground state, and the light hole effective masses in the growth direction are strongly reduced while the in-plane effective masses are considerable. Quantitative calculation of the valence intersubband transition between two light hole states in a 7nm tensile strained Si/Si0.55Ge0.45 quantum well grown on a relaxed Si0.5Ge0.5 （100） substrates shows a large absorption coefficient of 8400 cm^-1.