室温超高真空环境原子尺度Au/Si(111)-(7×7)不定域吸附的局域接触势能差测量技术  

Measurement of local contact potential difference of atomic scale Au/Si(111)-(7×7)delocalized adsorption state in room-temperature and ultra-high vacuum environment

作　　者：王慧云 冯婕 王旭东[1,2,3] 温阳 魏久焱 温焕飞 石云波[1,2,3] 马宗敏 李艳君[1,4] 刘俊 Wang Hui-Yun;Feng Jie;Wang Xu-Dong;Wen Yang;Wei Jiu-Yan;Wen Huan-Fei;Shi Yun-Bo;Ma Zong-Min;Li Yan-Jun;Liu Jun(State Key Laboratory of Dynamic Measurement Technology,North University of China,Taiyuan 030051,China;School of Instrument and Electronics,North University of China,Taiyuan 030051,China;Shanxi Province Key Laboratory of Quantum Sensing and Precision Measurement,North University of China,Taiyuan 030051,China;Department of Applied Physics,Graduate School of Engineering,Osaka University,Osaka 5650871,Japan)

机构地区：[1]中北大学,省部共建动态测试技术国家重点实验室,太原030051 [2]中北大学仪器与电子学院,太原030051 [3]中北大学,山西省量子传感与精密测量重点实验室,太原030051 [4]大阪大学,工学研究科精密科学应用物理学,大阪5650871

出　　处：《物理学报》2022年第6期84-93,共10页Acta Physica Sinica

基　　金：国家重点研发计划(批准号:2017YFE0130200,2018YFF01012502);国家自然科学基金(批准号:51727808,61874100,61503346,51635011);山西省“1331工程”重点学科建设项目(批准号:1331KSC);山西省自然科学基金(批准号:201701D121080,201803D421037,201901D211253);山西省回国留学人员科研资助项目(批准号:2021-115);2019年山西省高等学校创新人才支持计划资助的课题.

摘　　要：利用自制超高真空非接触调频开尔文探针力显微镜系统地研究了Au/Si(111)-(7×7)的结构和局域接触势能差.虽然扫描隧道显微镜已被广泛应用于原子尺度金属吸附半导体表面的研究,但仅局限在观测金属和半导体表面.开尔文探针力显微镜允许在原子尺度利用局域接触势能差直接测量各类平整表面不同位置的电荷,而成为更方便、更精确的电荷表征手段.本文通过在室温下利用开尔文探针力显微镜对Au吸附Si(111)-(7×7)表面的形貌及局域接触势能差原子尺度测量,同时建立相应的吸附模型和第一性原理计算,得到了Au/Si(111)-(7×7)最佳吸附位置的差分电荷密度分布图,并给出了Au在Si(111)-(7×7)表面的最佳吸附位置不定域移动的局域接触势能差关系,分析了Au原子在吸附过程中与Si表面之间电荷转移的机理.实验结果表明,Au/Si(111)-(7×7)吸附表面的局域接触势能差测量可以进行有效的Au与Si原子识别.本研究对推动表面电荷精密测量的发展具有重要意义.The structural properties and local contact potential difference of Au on Si(111)-(7×7)surface are studied by the homemade ultra-high vacuum non-contact Kelvin probe force microscope.Although scanning tunneling microscopy has been widely used to study the metal-adsorbed semiconductor surfaces on an atomic scale,the tunnel current measured by scanning tunneling microscopy is easy to lead the charge states to accidentally switch in the measurement process,and it is limited only to the observation of metal and semiconductor surfaces.Kelvin probe force microscope allows us to directly measure the charges at different positions of various flat surfaces by local contact potential difference on an atomic scale,which has become a more convenient and accurate means of charge characterization.In this paper,the topography and local contact potential difference of Au adsorbed Si(111)-(7×7)surface are measured on an atomic scale by Kelvin probe force microscope at room temperature,and the corresponding adsorption model and first principle calculation are established.The differential charge density distribution of the stable adsorption position of Au/Si(111)-(7×7)is obtained,and the local contact potential energy difference relationship of the stable adsorption position of Au on Si surface is given,The mechanism of charge transfer between Au atom and Si(111)-(7×7)surface during adsorption is analyzed.The experimental results show that at room temperature,single Au atom will form triangular delocalized adsorption state in the half unit cell of Si(111)-(7×7).The delocalized adsorption state is due to the fact that the moving speed of a single Au atom in the HUC is faster than the scanning speed of Kelvin probe force microscope,and the local contact potential difference measurement of Au/Si(111)-(7×7)adsorbed surface can effectively identify Au and Si atoms.Obviously,this research is of great significance in promoting the development of surface charge precision measurement,and is expected to provide some insights into the c

关 键 词：开尔文探针力显微镜 Au/Si(111)-(7×7) 表面 局域接触势能差 

分 类 号：O647.3[理学—物理化学]