报告人：邀请人： 李 海 教 授

报告地点：科技创新大楼C501室

Compared to conventional semiconductor heterostructures, van der Waals heterostructures (vdWHs) based on two-dimensional materials (2DMs) are readily fabricated by direct chemical-vapor-deposition growth or wet/dry transfer. Those vdWHs have ultraclean and atomically sharp interfaces, providing a versatile platform for studying interface-related properties. Also, the material choice of the components, layer thickness and interlayer twist angle q widely enrich the vdWHs and provide multiple degrees of freedom to engineer their optical and electronic properties. Raman spectroscopy is widely used to monitor the crystal quality, polytypism, doping, defects, strain, disorder, chemical modification, and relative orientation of 2DM flakes. In this talk, I will review the recent advances in the Raman spectroscopic study of two-dimensional materials, twisted bilayer two-dimensional materials and two-dimensional van der Waals heterostructures to quantitatively probe the interfacial coupling in the heterostructures and to map the phonon dispersions of the monolayer constituent in the twisted bilayer.

谭平恒，半导体所研究员，博士生导师，中国科学院大学岗位教授。2001年在中科院半导体所获博士学位, 之后到德国肖特基研究所从事博士后研究和英国剑桥大学访问学习。谭平恒研究员一直从事半导体低维纳米材料的光学和电学性质研究，至今已在Chem. Soc. Rev.，Nat. Mater.，Nat. Commun.，Phys. Rev. Lett.，J. Am. Chem. Soc.和Sci. Bull.等国内外物理期刊发表论文180余篇。曾于2003年获全国百篇优秀博士学位论文，2012年获国家杰出青年研究基金资助，2015年获黄昆物理研究奖，。目前任中国物理学会理事，中国物理学会秋季物理年会组委会委员，中国物理学会光散射专业委员会主任委员，中科院半导体所学位委员会主任，国际拉曼光谱学术会议（ICORS）指导委员会委员，以及《Semiconductor Science and Technology》、《npj 2D Materials and Applications》、《Journal of Raman Spectroscopy》、《半导体学报》和《光散射学报》等学术期刊编委。