Direct measurements of conductivity and mobility in millimeter-sized single-crystalline graphene via van der Pauw geometry  

作　　者：马瑞松 郇庆 吴良妹 严佳浩 张余洋 鲍丽宏 刘云圻 杜世萱 高鸿钧 

机构地区：[1]Institute of Physics & School of Physical Sciences, University of Chinese Academy of Sciences (CAS), Beijing 100190, China [2]CAS Key Laboratory of Vacuum Physics, University of Chinese Academy of Sciences, Beijing 100049, China [3]Beijing Key Laboratory for Nanomaterials and Nanodevices, Beijing 100190, China [4]Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China

出　　处：《Chinese Physics B》2017年第6期307-314,共8页中国物理B（英文版）

基　　金：supported by the Science Fund from the Ministry of Science and Technology of China(Grant No.2013CBA01600);the National Key Research&Development Project of China(Grant No.2016YFA0202300);the National Natural Science Foundation of China(Grant Nos.61474141,61674170,61335006,61390501,51325204,and 51210003);the Chinese Academy of Sciences(CAS) and Youth Innovation Promotion Association of CAS(Grant No.20150005)

摘　　要：We report the direct measurements of conductivity and mobility in millimeter-sized single-crystalline graphene on SiO2/Si via van der Pauw geometry by using a home-designed four-probe scanning tunneling microscope（4P-STM）. The gate-tunable conductivity and mobility are extracted from standard van der Pauw resistance measurements where the four STM probes contact the four peripheries of hexagonal graphene flakes, respectively. The high homogeneity of transport properties of the single-crystalline graphene flake is confirmed by comparing the extracted conductivities and mobilities from three setups with different geometry factors. Our studies provide a reliable solution for directly evaluating the entire electrical properties of graphene in a non-invasive way and could be extended to characterizing other two-dimensional materials.We report the direct measurements of conductivity and mobility in millimeter-sized single-crystalline graphene on SiO2/Si via van der Pauw geometry by using a home-designed four-probe scanning tunneling microscope（4P-STM）. The gate-tunable conductivity and mobility are extracted from standard van der Pauw resistance measurements where the four STM probes contact the four peripheries of hexagonal graphene flakes, respectively. The high homogeneity of transport properties of the single-crystalline graphene flake is confirmed by comparing the extracted conductivities and mobilities from three setups with different geometry factors. Our studies provide a reliable solution for directly evaluating the entire electrical properties of graphene in a non-invasive way and could be extended to characterizing other two-dimensional materials.

关 键 词：graphene conductivity MOBILITY four-probe measurement van der Pauw method 

分 类 号：TQ127.11[化学工程—无机化工]