双轴向应变对单层GeSe气体传感特性的影响  

Effect of biaxial strain on the gas-sensing of monolayer GeSe

作　　者：卢群林 杨伟煌 熊飞兵 林海峰 庄芹芹 Lu Qun-Lin;Yang Wei-Huang;Xiong Fei-Bing;Lin Hai-Feng;Zhuang Qin-Qin(Fujian Key Laboratory of Optoelectronic Technology and Devices,School of Opto-electronic and Communication Engineering,Xiamen University of Technology,Xiamen 361024,China;Engineering Research Center of Smart Microsensors and Microsystems,Ministry of Education,College of Electronics and Information,Hangzhou Dianzi University,Hangzhou 310018,China)

机构地区：[1]厦门理工学院光电与通信工程学院,福建省光电技术与器件重点实验室,厦门361024 [2]杭州电子科技大学电子信息学院,智能微传感器与微系统教育部工程研究中心,杭州310018

出　　处：《物理学报》2020年第19期239-247,共9页Acta Physica Sinica

基　　金：浙江省公益技术应用研究计划项目(批准号:LGG19F040003);国家自然科学基金(批准号:61704040);福建省自然科学基金(批准号:2016J01684,2018J01568);福建省中青年教师教育科研项目(批准号:JAT190671)资助的课题.

摘　　要：采用第一性原理计算方法,通过在吸附了H2,H2O,CO,NH3,NO,NO2等气体分子的单层GeSe上施加–8%—8%的双轴向应变,从微观角度阐明应变对吸附体系电子性质的影响及其内在机理.计算结果表明,对于CO,NH3和NO气体分子在–8%—8%,以及NO2分子在–8%—6%的双轴向应变范围内,单层GeSe具备成为气体传感器的应用潜力.较大的压缩应变(–6%—–8%)有助于提高单层GeSe对CO和NO气体的响应速度和敏感性.The adsorptions of various gas molecules(H2,H2O,CO,NH3,NO,and NO2)on monolayer GeSe versus the external biaxial strain in a range of–8%to 8%are investigated by first-principles calculations.The band structures,the equilibrium heights,the adsorption energy,and the amount of charge transfer are determined.The calculated results show that monolayer GeSe changes from indirect-to-direct and semiconducting-tometallic under a certain biaxial strain.The adsorbed gas molecules hardly change the band gap of monolayer GeSe even under a biaxial strain in the whole range from–8%to 8%.The calculated adsorption energies under different strains reveal that the external biaxial strain has no significant effect on the adsorption stability of the gas molecules on monolayer GeSe,so it seems impossible to promote the desorption of the gas molecules by applying strain.It is found that NO2 under the biaxial tensile strain of 8%tends to be bound with the monolayer GeSe by chemical bond which leads to being-difficult-to-desorb.Besides that case,the investigated gas molecules are physisorbed on the GeSe surface and have a certain probability of adsorption and desorption.The charge transfers of CO,NH3,NO and NO2 adsorbed systems under the biaxial strain from–8%to 8%change somehow but are still non-negligible,while for H2 and H2O,their charge transfers are too small to be detected by the monolayer-GeSe-based gas-sensor.Thus,due to the moderate adsorption energy and charge transfer,monolayer GeSe can be a promising candidate as a sensor for CO,NH3 and NO under the biaxial strain from–8%to 8%,and for NO2 in the range from–8%to 6%.It is worth noting that because of the appropriately lower adsorption energy and bigger charge transfer,a bigger biaxial compressive strain,ranging from–6%to–8%,can improve the response speed and sensibility to CO and NO of monolayer GeSe.Furthermore,the effect of the external biaxial strain on the adsorption stability and the charge transfer are discussed based on the two mechanisms of charge transfers

关 键 词：气体传感 应变 单层GeSe 第一性原理 

分 类 号：TP212[自动化与计算机技术—检测技术与自动化装置]