Wide Bandgap II-VI Compounds for Quantum Cascade Lasers

用于量子级联激光器的宽禁带 II-VI 化合物

• 批准号: 0217646
• 负责人: Maria Tamargo
• 金额: $ 24万
• 依托单位: CUNY City College
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-10-01 至 2005-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0217646&HistoricalAwards=false
• 关键词: Wide; Bandgap; II; VI; Compounds

Quantum Cascade Lasers (QCLs) are a new kind of semiconductor laser based on intersubband transitions within a quantum well (QW). Among the more attractive features of QCLs are their unipolar transport, high power emission, ultrafast modulation (100GHz) and generation of wavelengths in the mid and far infrared, not ever obtained before. Considerable advances have been achieved in the development of the QCLs during the last few years, which have led to the appearance of the first commercial thermoelectrically cooled QCLs.However, there are still many limitations of these lasers. A critical one is the unavailability of QCLs operating in continuous wave (CW) mode at room temperature (RT). Another is the absence of QCLs operating at short wavelengths, such as l=1.55mm, needed to develop ultrafast optical communications. Both of these drawbacks are due to insufficient electron confinement in the materials combinations presently used. Therefore, new systems based on wide band gap materials are required.This program proposes to explore the use of wide bandgap II-VI materials for the development of QCLs. The large conduction band offsets and deep QWs offered by the II-VI semiconductors, such as ZnCdMgSe/ZnCdSe, provide the possibility of higher electron confinement (and consequently the opportunity to obtain QCLs operating at RT in CW mode) and of QCLs that operate at 1.55mm for a new generation of ultrafast optical communications lasers. An important issue in favor of using II-VI semiconductors for QCLs is the fact that these devices are unipolar and do not require p-type doping, which traditionally has been a problem in most of the II-VI systems. While GaN-based materials are an alternative, the difficulties associated with the growth of high quality multi-layered structures of the nitride materials make them less attractive than the near lattice-matched, well-developed II-VI material systems.Several II-VI systems that are particularly promising for QCLs with low threshold current, operating at RT and some of them that should be able to generate emission at 1.55mm will be investigated. The QW properties, such as the energy levels available for intersubband transitions, will be investigated using modulation spectroscopy and other optical techniques. Such techniques have also been extensively utilized in the past by the PIs. Once a system has been identified to have potential for QCL applications, the QW structures will be optimized and incorporated in device structures to investigate the emission and lasing characteristics.

量子级联激光器（QCL）是一种基于量子阱内子带间跃迁的新型半导体激光器。QCL更吸引人的特性是它们的单极传输，高功率发射，超快调制（100 GHz）以及产生以前从未获得过的中红外和远红外波长。近几年来，准分子激光器的研究取得了很大的进展，出现了第一台商业化的热电冷却准分子激光器，但仍存在许多局限性。一个关键的问题是在室温（RT）下以连续波（CW）模式工作的QCL不可用。另一个原因是缺乏在短波长（如l= 1.55 mm）下工作的QCL，这是开发超快光通信所需的。这两个缺点都是由于目前使用的材料组合中的电子约束不足。因此，需要基于宽带隙材料的新系统。本计划建议探索使用宽带隙II-VI族材料开发QCL。由II-VI族半导体（例如ZnCdMgSe/ZnCdSe）提供的大导带偏移和深QW提供了更高电子约束（并且因此有机会获得在CW模式下在RT下操作的QCL）和在1.55mm下操作的QCL的可能性，用于新一代超快光通信激光器。有利于使用II-VI半导体用于QCL的一个重要问题是这些器件是单极的并且不需要p型掺杂，这在传统上是大多数II-VI系统中的问题。虽然GaN基材料是一种替代材料，但与氮化物材料的高质量多层结构的生长相关的困难使它们不如近晶格匹配的、开发良好的II-VI族材料系统有吸引力。在RT下运行，其中一些应该能够产生1.55mm的发射。量子阱的性质，如可用于子带间跃迁的能级，将使用调制光谱和其他光学技术进行研究。这些技术在过去也被PI广泛使用。一旦一个系统被确定为具有QCL应用的潜力，QW结构将被优化并结合到器件结构中，以研究发射和激光特性。