title: Subatomic deformation driven by vertical piezoelectricity from CdS ultrathin films.
abstract: Driven by the development of high-performance piezoelectric materials, actuators become an important tool for positioning objects with high accuracy down to nanometer scale, and have been used for a wide variety of equipment, such as atomic force microscopy and scanning tunneling microscopy. However, positioning at the subatomic scale is still a great challenge. Ultrathin piezoelectric materials may pave the way to positioning an object with extreme precision. Using ultrathin CdS thin films, we demonstrate vertical piezoelectricity in atomic scale (three to five space lattices). With an in situ scanning Kelvin force microscopy and single and dual ac resonance tracking piezoelectric force microscopy, the vertical piezoelectric coefficient (d 33) up to 33 pm·V(-1) was determined for the CdS ultrathin films. These findings shed light on the design of next-generation sensors and microelectromechanical devices.
authors.affiliation: School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.; International Laboratory for Adaptive Bio-nanotechnology (i-Lab), Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China.
authors.forename: Xuewen
authors.identifier: 0000-0002-9689-6678
authors.initials: X
authors.lastname: Wang
authors.affiliation: School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.
authors.forename: Xuexia
authors.initials: X
authors.lastname: He
authors.affiliation: Key Laboratory of Mesoscopic Chemistry of Ministry of Education and Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China.
authors.forename: Hongfei
authors.initials: H
authors.lastname: Zhu
authors.affiliation: School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
authors.forename: Linfeng
authors.initials: L
authors.lastname: Sun
authors.affiliation: School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.
authors.forename: Wei
authors.initials: W
authors.lastname: Fu
authors.affiliation: Centre for Micro-/Nano-electronics (NOVITAS), School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, Singapore.
authors.forename: Xingli
authors.initials: X
authors.lastname: Wang
authors.affiliation: School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.
authors.forename: Lai Chee
authors.initials: LC
authors.lastname: Hoong
authors.affiliation: School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.
authors.forename: Hong
authors.initials: H
authors.lastname: Wang
authors.affiliation: School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.
authors.forename: Qingsheng
authors.identifier: 0000-0002-3480-7908
authors.initials: Q
authors.lastname: Zeng
authors.affiliation: School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.
authors.forename: Wu
authors.initials: W
authors.lastname: Zhao
authors.affiliation: Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, Singapore 638075, Singapore.
authors.forename: Jun
authors.identifier: 0000-0002-9583-1346
authors.initials: J
authors.lastname: Wei
authors.affiliation: Key Laboratory of Mesoscopic Chemistry of Ministry of Education and Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China.
authors.forename: Zhong
authors.initials: Z
authors.lastname: Jin
authors.affiliation: School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
authors.forename: Zexiang
authors.initials: Z
authors.lastname: Shen
authors.affiliation: Key Laboratory of Mesoscopic Chemistry of Ministry of Education and Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China.; Department of Chemistry, Duke University, Durham, NC 27708, USA.
authors.forename: Jie
authors.initials: J
authors.lastname: Liu
authors.affiliation: International Laboratory for Adaptive Bio-nanotechnology (i-Lab), Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Zhang
authors.affiliation: Centre for Micro-/Nano-electronics (NOVITAS), School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, Singapore.; Center for Programmable Materials, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.; CINTRA CNRS/NTU/THALES, UMI 3288, Research Techno Plaza, 50 Nanyang Drive, Singapore 637553, Singapore.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Liu
mesh_terms: D019187:Cadmium Compounds / Q000737:chemistry*; D004560:Electricity; D004867:Equipment Design; D018625:Microscopy, Atomic Force; D016252:Microscopy, Scanning Tunneling; D053770:Nanowires / Q000737:chemistry; D013059:Spectrum Analysis, Raman; D013440:Sulfides / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D019187:Cadmium Compounds; D013440:Sulfides; C034939:cadmium sulfide
keywords: 2D materials; CdS thin films; Vertical piezoelectricity; sub-atom deformation