学术报告（11月1日 周四 16：00-17：30）

主持人：钟定永 教授

欢迎广大师生踊跃参与！

【报告摘要】

    Despite being a bona-fide bulk insulator, the surface of diamond presents a versatile platform for exploiting some of the extraordinary physical and chemical properties of diamond, leading to applications such as chemical/biological sensing and the development of high-power and high-frequency field effect transistors (FETs)¹. On one hand, bare diamond (001) surfaces are reactive, and can be readily functionalized by organic molecules through chemical reactions such as cycloaddition reaction. Hydrogen-terminated diamond surface, on the other hand, develops an intriguing two-dimensional (2D) p-type surface conductivity when exposed to appropriate surface adsorbate layer such as atmospheric water as a result of the surface transfer doping process.

    In the first part of the talk, I will describe our recent work in the engineering of diamond surface properties through surface functionalization². The implications of these new diamond surface terminations to potential applications in photochemistry and quantum sensing will be discussed. In the second part of the talk, I will describe our work on the surface transfer doping of diamond by a variety of solid-state acceptors³. I will show that by interfacing diamond with suitable materials a 2D hole conducting layer with metallic transport behaviours arises on diamond. Magnetotransport studies at low temperature reveal phase coherent transport in the 2D channel represented in the form of weak localisation and antilocalisation, and are analysed in the context of spin-orbit coupling induced by Rashba effect. We demonstrate that this surface conducting channel can be exploited to build diamond surface electronic devices such as metal-oxide semiconductor FETs (MOSFETs). Lastly, the prospects for constructing novel quantum devices on diamond surface by making use of this highly tunable 2D conducting layer on diamond are also explored.

References:

1. Pakes, C. I., Garrido, J. A., & Kawarada, H. MRS Bulletin, 39, 542-548 (2014).
2. Schenk, A. K., Tadich, A., Sear, M. J., Qi, D.-C., Wee, A. T. S., Stacey, A., & Pakes, C. I. (2016). Nanotechnology, 27, 275201 (2016).
3. Crawford, K. G. et al. Applied Physics Letters, 108, 042103 (2016); Crawford, K. G. et al. Scientific Reports, 8, 3342 (2018).

【报告人简介】

    During 1999 to 2003 Dr. Qi studied physics in Peking University for his undergraduate education before he moved to Singapore. After receiving his PhD degree in surface science from the National University of Singapore in 2009, he spent another two years as a research fellow at the same institute. In 2012, he joined the Institute of Materials Science and Engineering (IMRE) as a staff scientist working on organic electronic devices. He took up a faculty position as a lecturer in physics at La Trobe University in 2013. In 2016, Dr. Qi was awarded the prestigious ARC Future Fellowship to develop high-performance diamond surface electronics and quantum devices. In 2018, Dr. Qi joins the Queensland University of Technology as a Senior Lecturer.Dr. Qi’s research interests lie in the area of experimental condensed matter physics and material physics, focusing on creating, understanding, and controlling at nanoscale the surfaces and interfaces of functional materials to develop new technologies and material platforms for the next-generation devices. He is particularly interested in using advanced synchrotron light to examine important interface phenomena and physics essential to enable electronic devices based on emerging materials including diamond and organic semiconductors. Dr. Qi has published more than 80 articles in internationally refereed journals including Nature Nanotechnology, Physical Review Letters, Journal of the American Chemical Society, and Advanced Materials, with an H-index of 28.

    祁东晨，2003年获得北京大学物理系学士，2009年获新加坡国立大学凝聚态物理博士学位。2009 ~ 2013年先后在新加坡国立大学和新加坡材料科学与工程研究所Institute of Materials Science and Engineering (IMRE) 任研究员。2013年起任拉筹伯大学(La Trobe University)物理系讲师，澳大利亚同步辐射中心顾问。2017年因“开发高性能金刚石表面电子与量子器件”获得澳大利亚国家基金委杰出青年基金 (ARC Future Fellowship)。2018年加入昆士兰科技大学任高级讲师。祁东晨博士主要从事实验凝聚态物理和材料物理研究，关注于在纳米尺度上创造、理解和控制功能性材料表界面，为下一代电子器件的开发提供新技术和新平台；擅长利用先进的同步辐射技术研究新兴材料（包括金刚石和有机半导体）电子器件的界面物理现象。在国际重要刊物上Nat. Nanotech., Phys. Rev. Lett., J. Am. Chem. Soc., Adv. Mater.等发表论文80余篇(H-index = 28)。