湖南大学“天马材料研究论坛”第146期第一讲
题 目：“Direct bandgap Ge by design for a CMOS compatible light source”
报告人：骆军委 研究员（中国科学院半导体研究所研究员）
地 点：工程实验大楼440多媒体报告厅
时 间：2018年11月10日（周六）下午2:30-3:30
主持人：潘安练 教授
邀请人：材料科学与工程学院
承办人：材料学院“天马材料研究论坛”日常工作小组
报告人简介：
骆军委，中国科学院半导体研究所研究员，半导体超晶格国家重点实验室副主任兼计算材料和器件研究组长，。2006年在中国科学院半导体研究所获得博士学位。2007－2014年在美国可再生能源国家实验室工作，先后担任博士后、永久职位科学家、资深科学家。2014年回国工作。研究领域为半导体物理与器件模拟, 在半导体自旋轨道耦合效应、硅基半导体信息功能材料理论设计和发展原子精度全量子力学器件模拟方法等领域开展了系统的研究，已在包括Nature子刊 (5篇)、Phys. Rev. Lett. (6篇)、JACS (1篇)、Nano Lett. (7篇)等国际学术期刊上发表SCIE论文60余篇。多次在APS、ACS和E-MRS等国际重要会议做邀请报告和分会主席。
报告内容：
Silicon is one of the most important semiconductor materials. Although it has been the mainstays for modern electronics, it is not widely used for light emitting sources because bulk silicon is an inefficient emitter, a result of indirect bandgap. Direct epitaxial growth of III-V nanostructures on silicon substrates is one of the most promising candidates for realizing photonic devices on a silicon platform. The major issue of monolithic integration of III-V on group IV platform is the formation of high-density threading dislocations (TDs). The TDs are caused by the lattice mismatch between the III-V materials and group IV substrates, for instance, GaAs has 4% lattice mismatch with Si. The propagation of TDs will cause high ratio of non-radiative recombination centre in III-V epitaxial active region. To stop the TD propagation, defects filter layers (DFLs) formed by InGaAs/GaAs strained-layer superlattices (SLSs) have been applied, which significantly reduce the density of TDs from ~1010/cm2 at the interface between III-V and Si to <106/cm2 in III-V active region. As a zero-dimensional material, quantum dot (QD) has three-dimensional quantum confinements, which create delta-function like density of states. Therefore, QD lasers have low threshold currents, temperature insensitive operation, and less sensitivity to threading dislocations, which are the ideal candidate to form active region in III-V lasers grown on group IV substrates. High performance QD lasers grown on Si substrates have been developed at UCL for last few years. Here, I will show our recent development of InAs/GaAs QD lasers monolithically grown on a Si substrate, and the roadmap towards silicon-based photonics and photonic-electronic integration, and provide a route towards cost-effective monolithic integration of III-V devices on Si platform.
