改性石墨烯SO_2气敏性质的第一性原理研究  

First-principles study on SO_2 gas sensitivity of modified graphene

作　　者：马玲 马欢 张建宁 林雪玲 张建民[2] MA Ling;MA Huan;ZHANG Jian-Ning;LIN Xue-Ling;ZHANG Jian-Min(School of Physics and Electronic-Electrical Engineering,Ningxia University,Yinchuan 750021,China;College of Physics and Information Technology,Shaanxi Normal University,Xian 710062,China)

机构地区：[1]宁夏大学物理与电子电气工程学院,银川750021 [2]陕西师范大学物理学与信息技术学院,西安710199

出　　处：《原子与分子物理学报》2018年第2期333-340,共8页Journal of Atomic and Molecular Physics

基　　金：宁夏自然科学基金(NZ15057);宁夏大学科学研究基金(ZR1406);国家自然科学基金(11664033;11764032)

摘　　要：为了寻求高灵敏度的石墨烯基的SO_2气体传感器,本文采用基于密度泛函理论的第一性原理方法,研究纯净石墨烯(PG)、单空位缺陷(SVG)、SW缺陷(SWG)、Mn掺杂修饰的石墨烯(Mn-PG)及掺杂和缺陷共修饰的石墨烯(Mn-SVG和Mn-SWG)对SO_2分子的吸附特性.研究表明:PG和SWG对SO_2分子的吸附作用较弱,对SO_2分子不具有敏感性;SO_2分子在SVG表面的吸附能够有效调控其电子结构的变化,使其由金属性转变为半金属性,但其吸附能较低(0.636 eV);结合了Mn掺杂和SV缺陷的Mn-SVG基底尽管增大了与SO_2分子相互作用,但未能引起该体系电子结构和磁性的明显改变;相比之下,SO_2分子在Mn-PG和Mn-SWG基底上具有较强的吸附稳定性;同时,该分子吸附可诱发Mn-PG和Mn-SWG体系磁矩的急剧降低和电导率的显著变化,故可作为探测和清除环境中SO_2分子理想材料.该研究为设计新型石墨烯气体传感器提供理论参考.To search for high sensitivity of graphene-based gas sensors for SO 2 gas,the adsorption of SO 2 molecules on pristine graphene(PG)and modified graphene,including single vacancy defect(SVG),Stone-Wales defect(SWG),Mn dopant(Mn-PG)and combining Mn dopant and defect(Mn-SVG and Mn-SWG),were investigated by first-principles based on density functional theory.It is found that SO 2 molecule undergoes weak interaction with PG and SWG,indicating that PG and SWG are not sensitive to SO 2 molecule;For SVG,SO 2 adsorbing can effectively tune the change of electronic structure and SVG transforms from metallic to half-metallic.However,SO 2 is still weakly adsorbed on SVG with relatively small adsorption energy of 0.636 eV.The substrate of Mn-SVG combines Mn dopant and single vacancy in graphene to enhance its interaction with the gas,but it demonstrates few changes in the electrical structure and magnetism by SO 2 adsorption.Compared with other substrates,SO 2 molecule can be adsorbed steadily on Mn-PG and Mn-SWG and SO 2 adsorbing leads to remarkable reduction of magnetic moment and significant change in electrical conductivity for the system of Mn-PG and Mn-SWG.Therefore,Mn-PG and Mn-SWG can behave as ideal materials for detecting and removing SO 2 gas in environment.Our work provides theoretical reference to design novel graphene-based gas sensor.

关 键 词：SO2吸附 改性石墨烯 气敏性 密度泛函理论 

分 类 号：O474[理学—半导体物理]