Tuning Electronic Properties of Two-dimensional Quantum Films








             Modern molecular beam epitaxial growth techniques and in particular, the recent breakthrough in fabrication of freestanding two-dimensional (2D) crystals such as graphene layers have opened the way for fundamental study of novel quantum phenomena in 2D quantum films a few atomic layers thick. The physical properties of 2D quantum films are sensitive to structural changes because of the more direct manifestation of quantum effects at reduced dimensionality. In this talk, I will present theoretical proposals for tuning electronic properties of 2D films by structural changes, focusing on doping effects.

Doping, an essential element for manipulation of electronic transport in traditional semiconductor industry, is widely expected to play important role as well in control of transport properties in 2D quantum films. However, traditional theory of electronic disorder predicts that doping in 2D systems leads to carrier localization, limiting practical applications of doping because of poor carrier mobility. We proposed a novel concept [1, 2], namely, confined doping, to significantly increase carrier mobility in 2D films. In our approach, distribution of dopants in a 2D film is confined within a particular layer in the film so that the doped film becomes a coupled system comprising a doped subsystem and a perfect crystalline subsystem. We showed that carrier mobility in a bilayer 2D film with confined doping exhibits a rather counterintuitive behavior in the regime of heavy doping, namely, the larger the concentration of dopants the higher the carrier mobility. Application of the model to bilayer graphene systems will be discussed [3].



[1] J.X. Zhong and G.M. Stocks, Nano Lett. 6, 128 (2006).

[2] J.X. Zhong and G.M. Stocks, Phys. Rev. B 75, 033410 (2007).

[3] Y.L. Mao and J.X. Zhong, Nanotechnology 19, 205708 (2008).





获国家教学成果二等奖、湖南省高等教育教学成果一等奖、湖南省科技进步二等奖、教育部科技进步三等奖、全国优秀青年教师基金、湖南省首届十大杰出青年科技工作者、美国R&D Magazine期刊年度世界顶尖25项微纳技术奖等科研奖励。

主要从事凝聚态物理、功能材料、微纳电子学研究。在国内外重要学术刊物上发表论文90余篇;多次在重大国际会议上做邀请报告,包括美国物理协会年会邀请报告和美国纳米技术大会重点报告等。研究成果被发表在Nature、Nature Nanotechnology等期刊的文章验证、重点介绍和评价,被SCI论文引用410余次。主持或参加国家自然科学基金、教育部科技创新重大项目培育基金等国家级或部省级项目10余项。