Nanowire heterostructures for intersubband lasers

本研究的目的是探讨量子点内生长的半导体纳米线太赫兹激光器，在室温下运行。半导体量子点材料是次能级间探测器和发射器的优秀候选者，因为它们在光学声子散射的辅助下显著抑制电子能量弛豫。合作研究工作将分三个阶段进行：（一）合理增长的轴向和核/壳异质结构的纳米线形成耦合量子点，（二）测量和表征纳米线子级间吸收使用红外光谱，和（三）调查纳米线量子点超晶格的电致发光和受激发射。知识产权的优点是使用纳米线量子点的intersublevel级联激光器，这有望解决传统的平面太赫兹量子级联激光器的基本限制，其中非辐射声子辅助弛豫防止室温操作。无金属催化剂的选择性区域MOCVD外延将用于使用光刻定义的氧化物生长掩模生长高纵横比InGaAs/GaAs半导体纳米线，其中嵌入轴向量子点用于有效的点到点隧穿传输。更广泛的影响是开发一类具有高度工程量子电子特性的低维III-V半导体纳米材料。这项工作将推进太赫兹材料和技术，其中源和探测器是传感，成像和光谱学所需的。该计划还将通过实验室研究参与，补充课程开发和科学重点社区K？12参与通过学生代表不足的少数民族社团和加州大学洛杉矶分校工程卓越和多样性中心，有针对性地招募本科生研究人员的计划已经到位。

The objective of this research is to investigate quantum-dots grown within semiconductor nanowires for terahertz lasers that operate at room-temperature. Semiconductor quantum-dot materials are excellent candidates for intersublevel detectors and emitters because of their dramatic suppression of electronic energy relaxation assisted by optical-phonon scattering. A collaborative research effort will proceed in three stages: (i) rational growth of axial and core/shell heterostructures in nanowires for the formation of coupled-quantum dots, (ii) measurement and characterization of nanowire intersublevel absorption using infrared spectroscopy, and (iii) investigation of nanowire quantum-dot superlattices for electroluminescence and stimulated emission. The intellectual merit is the use of nanowire quantum-dots for intersublevel cascade lasers, which are expected to solve a fundamental limitation of conventional planar THz quantum-cascade lasers, where non-radiative phonon-assisted relaxation prevents room temperature operation. Selective-area MOCVD epitaxy without metal catalysts will be used to grow high-aspect ratio InGaAs/GaAs semiconductor nanowires using lithographically defined oxide growth masks, with embedded axial quantum dots for efficient dot-to-dot tunneling transport. The broader impacts are the development of a class of low-dimensional III-V semiconductor nanomaterials with highly engineerable quantum-electronic properties. This work will advance terahertz materials and technology, where sources and detectors are desired for sensing, imaging, and spectroscopy. The program will also integrate education and research in training of undergraduate/graduate students through laboratory research participation, complementary coursework development, and scientifically focused community K?12 involvement. A plan is in place for focused recruiting of undergraduate student researchers through student underrepresented minority societies and the UCLA Center for Engineering Excellence and Diversity.