title: Tunable electrical properties of silicon nanowires via surface-ambient chemistry.
abstract: p-Type surface conductivity is a uniquely important property of hydrogen-terminated diamond surfaces. In this work, we report similar surface-dominated electrical properties in silicon nanowires (SiNWs). Significantly, we demonstrate tunable and reversible transition of p(+)-p-i-n-n(+) conductance in nominally intrinsic SiNWs via changing surface conditions, in sharp contrast to the only p-type conduction observed on diamond surfaces. On the basis of Si band energies and the electrochemical potentials of the ambient (pH value)-determined adsorbed aqueous layer, we propose an electron-transfer-dominated surface doping model, which can satisfactorily explain both diamond and silicon surface conductivity. The totality of our observations suggests that nanomaterials can be described as a core-shell structure due to their large surface-to-volume ratio. Consequently, controlling the surface or shell in the core-shell model represents a universal way to tune the properties of nanostructures, such as via surface-transfer doping, and is crucial for the development of nanostructure-based devices.
authors.affiliation: Centre of Super-Diamond and Advanced Films (COSDAF) and Department of Physics and Materials Science, City University of Hong Kong, Hong Kong SAR, China.
authors.forename: G D
authors.initials: GD
authors.lastname: Yuan
authors.forename: Y B
authors.initials: YB
authors.lastname: Zhou
authors.forename: C S
authors.initials: CS
authors.lastname: Guo
authors.forename: W J
authors.initials: WJ
authors.lastname: Zhang
authors.forename: Y B
authors.initials: YB
authors.lastname: Tang
authors.forename: Y Q
authors.initials: YQ
authors.lastname: Li
authors.forename: Z H
authors.initials: ZH
authors.lastname: Chen
authors.forename: Z B
authors.initials: ZB
authors.lastname: He
authors.forename: X J
authors.initials: XJ
authors.lastname: Zhang
authors.forename: P F
authors.initials: PF
authors.lastname: Wang
authors.forename: I
authors.initials: I
authors.lastname: Bello
authors.forename: R Q
authors.initials: RQ
authors.lastname: Zhang
authors.forename: C S
authors.initials: CS
authors.lastname: Lee
authors.forename: S T
authors.initials: ST
authors.lastname: Lee
mesh_terms: D003198:Computer Simulation; D003460:Crystallization / Q000379:methods*; D004553:Electric Conductivity; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008956:Models, Chemical; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods*; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D012825:Silicon / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D046911:Macromolecular Substances; D012825:Silicon