硒化锗纳米片在氧气和丁烷气体中的电导性能  

Electrical conductivity of germanium selenide nanosheets in oxygen and butane

作　　者：戴芳博 袁健美[2] 许凯燕 郭政 赵洪泉[3] 毛宇亮 Dai Fang-Bo;Yuan Jian-Mei;Xu Kai-Yan;Guo Zheng;Zhao Hong-Quan;Mao Yu-Liang(School of Physics and Optoelectronic,Xiangtan University,Xiangtan 411105,China;School of Mathematics and Computational Science,Xiangtan University,Xiangtan 411105,China;Chongqing Institute of Green and Intelligent Technology,Chinese Academy of Sciences,Chongqing 400714,China)

机构地区：[1]湘潭大学物理与光电工程学院,湘潭411105 [2]湘潭大学数学与计算科学学院,湘潭411105 [3]中国科学院重庆绿色智能技术研究院,重庆400714

出　　处：《物理学报》2021年第17期305-312,共8页Acta Physica Sinica

基　　金：湖南省自然科学基金(批准号:2019JJ40280);湖南省重点领域研发计划(批准号:2019GK2101);湖南省学位与研究生教育改革研究项目(批准号:2020JGYB097,2020JGYB098);湖南省大学生创新性研究项目(批准号:S201910530020)资助的课题.

摘　　要：利用机械剥离和高温减薄方法制备了厚度约为5 nm的GeSe纳米片,并通过设计实验装置测试了GeSe纳米片在不同浓度氧气(O_(2))和丁烷(C_(4)H_(10))气体中的电导性能.结果表明,随着氧气浓度的增加,GeSe纳米片在相同电压下所测得的电流增大,而在丁烷气体中所测得的电流减小.通过第一性原理计算发现,O_(2)分子从GeSe获得电子.气体浓度越大,P型半导体GeSe主要载流子空穴的浓度也越大,从而电导率增大.当GeSe吸附丁烷气体时,随着丁烷气体浓度的增加,相同电压下电导率减小.其原因可归结为GeSe薄膜器件在加工过程中从空气中吸附了O_(2)分子,由于薄膜中存在较高密度的Se空位,导致O_(2)的高密度吸附.从而导致在吸附还原性气体时,丁烷气体易失电子.即电子从丁烷气体分子中转移到GeSe薄膜表面与空穴中和,降低了GeSe薄膜中的载流子空穴浓度,从而降低电导率.本文的研究有助于GeSe纳米片在氧气和丁烷气中的光电器件应用.As a type of two-dimensional(2D)semiconductor material,2D germanium selenide(GeSe)exhibits excellent optoelectronic properties,and has potential applications in optoelectronic devices.The GeSe is a layered material with weak van der Waals interaction.Because of the high brittleness of GeSe,it is not easy to obtain 2D GeSe samples only by mechanical peeling technique.In order to obtain a thinner GeSe sheet,we use heat treatment to thin the bulk GeSe at a high temperature in vacuum.The GeSe samples obtained by mechanical peeling are placed in a tubular furnace with a pressure of 5×10^(-4) Pa for high temperature heating and thinning.In order to explore the better thinning effect,we set four temperatures to be at 320,330,340 and 350℃,respectively.After high temperature thinning,the samples are characterized and observed by atomic force microscope(AFM),scanning electron microscope(SEM),Raman spectrometer and photoluminescence(PL)spectrometer.From the above experiments,the GeSe nanosheet with a thickness of about 5 nm is prepared by mechanical peeling and high temperature thinning technology.Then,the electrical conductivities of GeSe nanosheets in oxygen(O_(2))and butane(C_(4)H_(10))with different concentrations are evaluated by our designed experimental device.The results show that with the increase of oxygen concentration,the electrical conductivity of GeSe nanosheets increases.When the GeSe nanosheet is in butane gas,its conductivity under the same voltage decreases with the increase of the concentration of butane gas.In order to further analyze the mechanism of gas adsorption on GeSe nanosheets,we carry out the first-principles calculations.Our calculation results show that the adsorption energy of GeSe nanosheets for oxygen and butane is–4.555 eV and–4.865 eV,respectively.It is shown that both adsorption systems have a certain stability.The adsorption energy of C_(4)H_(10) is smaller than that of O_(2),which corresponds to the smaller layer spacing of C_(4)H_(10) than that of O_(2) on GeSe surface.From Bad

关 键 词：GeSe 纳米片 电导 气体吸附 第一性原理 

分 类 号：TQ134.31[化学工程—无机化工] TB383.1[一般工业技术—材料科学与工程]