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Prof. Huiyun Liu: Silicon-based III-V Quantum-Dot Laser Diodes for Silicon Photonics
学术地点 工程实验大楼244、240多媒体报告厅 主讲人 University College London Huiyun Liu
讲座时间 2018年7月16日(周一)下午3:00-4:30​

湖南大学“天马材料研究论坛”第131期
题   目:“Silicon-based III-V Quantum-Dot Laser Diodes for Silicon Photonics”
报告人: Huiyun Liu Professor(Department of Electronic and Electrical Engineering, University College London)
地   点:工程实验大楼244、240多媒体报告厅
时   间:2018年7月16日(周一)下午3:00-4:30
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


报告摘要:

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 [1-4]. Here, I will show our recent development of InAs/GaAs QD lasers monolithically grown on a Si substrate. Low threshold current density (Jth) of 62.5 A/cm2, which corresponds to 12.5 A/cm2 for each of the five QD layers, has been demonstrated under cw operation at room temperature. The lasing wavelength is at 1315 nm. The output power measured from both facets is as high as 105 mW at an injection current density of 650 A/cm2, with no evidence of power saturation up to this current density. The ageing test was performed at a fixed temperature of 26 oC, with the output power monitored for a constant cw drive current of 210 mA. An extrapolated mean time to failure of over 100,158 hours was demonstrated here. These results are a major step towards silicon-based photonics and photonic-electronic integration, and provide a route towards cost-effective monolithic integration of III-V devices on Si platform.

硅是最重要的半导体材料之一。尽管硅已成为现代电子学的支柱,由于硅块体具有间接带隙,导致它作为发射器效率极低,因此无法在光发射源中得到广泛的应用。在硅基底上直接外延生长的三五族纳米结构,最有希望突破在硅平台实现光子器件的瓶颈。而三五族材料在四族(硅)平台上实现单片集成电路,最大的问题是如何解决所形成的高密度穿透位错。穿透位错是由三五族材料与四族基底之间的晶格失配引起的,例如,GaAs与硅之间有4%的晶格失配。穿透位错的衍生,会在三五族外延活动区产生高比率的无辐射复合中心。为了阻止穿透位错的衍生,运用InGaAs/GaAs 应变层超晶格形成的缺陷过滤层,可以显著地减小穿透位错的密度(从三五族与硅界面处约1010/cm2减小至在三五族活动区小于106/cm2)。作为零维材料,量子点在三个维度均具有量子限域效应,拥有类狄拉克函数的态密度。因此,量子点激光器具有阈值电流低、温度影响小、穿透位错干扰低的优点,是形成硅基三五族激光器活性区的理想选择。在过去几年,伦敦大学学院在硅基高性能量子点激光器的开发中积累了大量的经验[1-4]。此次,我将展示我们最近在硅基InAs/GaAs 量子点激光器的研究进展。在连续光激发下,室温下激光器可以获得 62.5 A/cm2的低阈值电流密度,相当于在五个量子点应变层中12.5 A/cm2。激射波长在1315 nm。在注入电流密度为650 A/cm2条件下,所测的输出功率高达105 mW。在恒定连续波驱动电流(210 mA)和26℃测试条件下,寿命可达158小时。这在硅基光子学和光电子学集成上实现了重大迈步,同时为三五族器件在硅平台的集成提供了一个简单有效的方法。


1. Liu, H., Wang, T., Jiang, Q., Hogg, R., Tutu, F., Pozzi, F. and Seeds, A., Nat. Photonics 5, 416–419 (2011).

2. Chen, S., Tang, M., Wu, J., Jiang, Q., Dorogan, V.G., Benamara, M., Mazur, Y.I., Salamo, G.J., Smowton, P., Seeds, A. and Liu, H., ACS Photonics 1, 638–642 (2014).

3. Chen, S., Li, W., Wu, J., Jiang, Q., Tang, M., Shutts, S., Elliott, S., Sobiesierski, A., Seeds, J., Ross, I., Smowton, P., and Liu, H., Nat. Photonics 10 (5), 307 (2016)

4. Wang, Y.,  Chen, S., Yu, Y., Zhou, L., Liu, L., Yang, C., Liao, M., Tang, M., Liu, Z., Wu, J., Li, W., Ross, I., Seeds, A., Liu, H., Yu, S., Optica 5, 528-533 (2018)


报告人简介:

Huiyun Liu : PhD Thesis is on III-V quantum-dot materials and laser diodes form Institute of Semiconductor, Chinese Academy of Sciences at November 2001. After receiving his PhD, he joined the EPSRC National Centre for III-V Technologies at Sheffield University. In 2007, he was awarded Royal Society University Research Fellow, and started his academic career by taking Senior Lecturer (as Associate Professor in US) position in the Department of Electronic and Electrical Engineering at University College London with commissioning the first new Molecular Beam Epitaxy reactor in central London. In 2012, he was promoted as Chair of Semiconductor Photonics at University College London. His current research interest concentrates on the nanometre-scale engineering of low-dimensional semiconductor structures (such as quantum dots and nanowires) by using Molecular Beam Epitaxy and the development of novel optoelectronic devices including lasers, detectors, solar cells, and modulators. He co-authored more than 300 papers and hold on several patents on silicon photonics.

Huiyun Liu ,2001年11月博士毕业于中科院半导体所,论文题目:三五族量子点材料与激光二极管。其后加入谢菲尔德大学物理科学研究委员会国家中心,并于2007年被授予英国皇家学会研究员。同年,任职英国伦敦大学学院电子与电气工程部高级讲师(相当于副教授),于2012年晋升为半导体光子学主席。主要从事分子束外延生长低维半导体纳米结构(如量子点、纳米线),并基于这些纳米结构展开新型光电器件(激光器、探测器、太阳能电池、调制器等)的探索研究。在国际顶级期刊发表论文300余篇,且持有多项硅光子学方面的专利。


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