柳忠元教授学术报告预告

报告题目：CVD-grown triangular WS₂ monolayer and bilayer crystals

----- Optical and electrical properties

报 告 人：柳忠元 教授 （燕山大学）

主 办：物理工程学院、激光研究所

时 间：2016年12月12日 9:00

地 点：物理楼313报告厅

Abstract：Triangular monolayer WS₂ crystals of size ranging from several to ~130 mm were grown by chemical vapor deposition (CVD). In fluorescence (FL) images and photoluminescence (PL) maps of intensity, the monolayer WS₂ crystals exhibit significantly enhanced light emission with increasing size. In monolayer crystals of large sizes, PL maps of intensity gives a fascinating pattern with stair-type enhanced intensity from the edges to the central region. As revealed by PL spectra at 77 K, the defects of S vacancies are lower in concentration in larger monolayer crystals and spatially inhomogeneous from the edges to central region, indicating the strong influence of size-dependent chemical composition on the optical property. Additionally, the monolayer WS₂ crystals of larger sizes (>30 mm) exhibit much more excellent electrical performance than those of smaller sizes (<20 mm). In our CVD-grown large monolayer WS₂ crystals, the achieved carrier mobility can be as high as 11.5 cm²V^-1s^-1. Based on the CVD-grown monolayer WS2 crystals and liquid-exfoliated SnS quantum dots, phototransistors were also fabricated to investigate the enhanced photoresponse of monolayer WS2 with the help of SnS quantum dots.

报告人简介：柳忠元，主要研究方向涉及以下几个领域：1）磁性薄膜、多层膜与器件；2）过渡族金属硫属化合物、黑磷等二维半导体材料的制备、性能与器件；3）过渡族金属碳化物硬质合金；4）超硬材料。主持承担了包括国家973课题、国家杰出青年基金、国家自然科学基金面上等12个项目的研究工作，并参加了国家973、国家自然基金委创新群体基金等5个项目的研究工作；2010年获国家杰出青年基金支持，2015年入选国家百千万人才工程，被授予国家“有突出贡献中青年专家”荣誉称号。迄今为止，已在Nature、Advanced Materials、ACS nano、Advanced Functional Materials、Physical Review Letters等国际著名学术杂志上发表被SCI收录论文160余篇，近五年60余篇。