中國科學(xué)技術(shù)大學(xué)李震宇教授做客第254期化苑講壇
報(bào)告題目：Mechanisms of Graphene Growth and Cutting
報(bào) 告 人 ：李震宇教授
報(bào)告時(shí)間：2017年5月5日（周五）下午14:30
報(bào)告地點(diǎn)：化學(xué)樓二樓一號(hào)會(huì)議室
邀 請 人 ：楊利明教授
報(bào)告人簡介：
李震宇，男，中國科學(xué)技術(shù)大學(xué)教授、合肥微尺度物質(zhì)科學(xué)國家實(shí)驗(yàn)室研究員、博士生導(dǎo)師。1999和2004年分別獲得中國科學(xué)技術(shù)大學(xué)物理學(xué)學(xué)士和物理化學(xué)博士學(xué)位。2004-2007年先后在美國馬里蘭大學(xué)和加州大學(xué)歐文分校從事博士后研究。2006年入選全國百篇優(yōu)秀博士學(xué)位論文作者，2008年入選教育部新世紀(jì)優(yōu)秀人才支持計(jì)劃，2011年獲中國科學(xué)院盧嘉錫青年人才獎(jiǎng)，2012年獲得國家自然科學(xué)基金委首屆優(yōu)秀青年科學(xué)基金項(xiàng)目資助，2015年獲中國化學(xué)會(huì)青年化學(xué)獎(jiǎng)。研究領(lǐng)域?yàn)槔碚撆c計(jì)算化學(xué)，主要通過電子結(jié)構(gòu)計(jì)算與分子模擬來研究材料物性和生長反應(yīng)機(jī)理。在包括Phys. Rev. Lett.、JACS、Angew. Chem. Int. Ed.在內(nèi)的國際學(xué)術(shù)期刊上發(fā)表論文120余篇，SCI引用3600余次，H因子為31。
報(bào)告內(nèi)容：
Graphene is an important material with unique properties and accordingly many potential applications. A promising way to produce high-quality wafer-size graphene is chemical vapor deposition (CVD) on metal surfaces. To improve the sample quality, it is important to understand the atomic details during graphene CVD growth. At the same time, to make devices, cutting graphene into different shapes is frequently required. In this talk, we focus on theoretical studies of the growth and cutting mechanisms. On Ir(111) surface, a universal lattice mismatch induced nonlinear growth mechanism is revealed via first principles calculations and kMC simulations. On Cu(111) surface, a significant carbon adsorption/diffusion induced surface relaxation characterized by the formation of bridging-metal (BM) structures is predicted. Dimer is found to be the growth feeding species, which leads to the experimentally observed diffusion-limited growth behavior. In CVD growth of graphene, hydrogen plays an important role and the dominant kinetic pathways are also determined by kMC simulations. Oxidative cutting of graphene proceeds with an unzipping mechanism, while graphene cutting by metal nanoparticles has a Pac-Man mechanism.
