新型正交相BN单层半导体有毒气体吸附性能及电输运性能的理论研究  

Theoretical study of adsorption properties and electrical transport performance of toxic gas molecules on novel orthorhombic BN monolayer semiconductor

作　　者：赵俊 姚璨 曾晖 Zhao Jun;Yao Can;Zeng Hui(School of Science,Nanjing University of Posts and Telecommunications,Nanjing 210023,China;School of Microelectronics,Nanjing University of Science and Technology,Nanjing 210094,China)

机构地区：[1]南京邮电大学理学院,南京210023 [2]南京理工大学微电子学院,南京210094

出　　处：《物理学报》2024年第12期338-349,共12页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:62174088,62371238)资助的课题。

摘　　要：低维材料表面的有毒气体吸附一直是分子传感器领域的研究热点.最近的新型正交相二维BN单层半导体材料引起了学者的广泛关注.基于第一性原理计算,本文研究了有毒气体分子(CO,H_(2)S,NH_(3),NO,NO_(2)和S02)在二维正交相BN单层表面的吸附特性.吸附能计算表明,正交相BN材料对所有气体的吸附均是能量有利的放热过程.NO_(2)和NH_(3)为化学吸附,其他体系均为物理吸附,且NO吸附后体系具有自旋极化的电子能带结构.态密度计算结果显示,NO_(2)和SO_(2)的吸附对费米能级附近的电子占据有显著影响.NO_(2)吸附后,体系的功函数和电子结构特性均明显改变,表明BN单层半导体材料对NO_(2)分子具有良好的吸附选择性和探测灵敏度.采用第一性原理结合非平衡格林函数方法计算了纳米电子器件的输运性能.在1 V偏压下,NO_(2)分子的吸附可使体系电流增大到6500 nA,显著增强了BN单层半导体器件的电输运性能,因此二维BN单层对NO_(2)气体吸附具有优异的探测敏感度.此外,轴向应力能够有效调控体系的吸附性能.研究表明,正交相BN单层材料对有毒气体具有优异的吸附性能,在新型有毒气体传感探测器件领域有较大的应用潜力.The adsorption properties of toxic gases on the surface of low-dimensional nanomaterials are a research hot topic and key issue for developing semiconductor sensors to detect toxic gas molecules.Recently,a novel orthorhombic BN monolayer has attracted extensive attention from researchers.Using first principles calculations,we investigate the adsorption properties of typical toxic gas molecules,such as CO,H_(2)S,NH_(3),NO,NO_(2),and SO_(2) molecules,on the surface of two-dimensional(2D)orthorhombic BN monolayer adsorption.The calculated adsorption energy show that the adsorptions of the above six molecules on the surface of BN monolayer are energy-favorable exothermic processes.It is found that NO_(2) and NH3 molecules are of chemical adsorption,while other systems are of physical adsorption,and NO adsorbing system exhibits a spin-polarized electronic band structure.The calculated density of states reveals that the adsorption of NO molecule and SO_(2) molecule have significant influences on the electronic structure near the Fermi level.Moreover,the adsorption of the NO_(2) molecule on the substrate exhibits remarkable variation of the work function,suggesting that the o-BN monolayer possesses excellent selectivity and sensitivity to NO_(2) molecule.In addition,we use first principles combined with non-equilibrium Green’s function to simulate the electrical transport properties of monolayered o-BN semiconductor based nanodevice with adsorption of typical toxic gas molecules.The I-Vb curve shows that the current through the nanodevice is 6500 nA for the NO_(2) molecule adsorbing system under 1 V bias voltage.The calculation results reveal that the adsorption of NO_(2) molecule on the o-BN monolayer can significantly enhance its electrical transport performance,and the o-BN monolayer possesses excellent sensitivity and selectivity to the NO_(2) gas molecule.The work function and the charge transfer can be effectively manipulated by tensile strain,indicating its potential application in anisotropic electronics.Our r

关 键 词：吸附 正交相BN 第一性原理 电输运 气体传感器 

分 类 号：O647.3[理学—物理化学] O469[理学—化学]