title: Modulating Electrical Properties of InAs Nanowires via Molecular Monolayers.
abstract: In recent years, InAs nanowires have been demonstrated with the excellent electron mobility as well as highly efficient near-infrared and visible photoresponse at room temperature. However, due to the presence of a large amount of surface states that originate from the unstable native oxide, the fabricated nanowire transistors are always operated in the depletion mode with degraded electron mobility, which is not energy-efficient. In this work, instead of the conventional inorganic sulfur or alkanethiol surface passivation, we employ aromatic thiolate (ArS(-))-based molecular monolayers with controllable molecular design and electron density for the surface modification of InAs nanowires (i.e., device channels) by simple wet chemistry. More importantly, besides reliably improving the device performances by enhancing the electron mobility and the current on-off ratio through surface state passivation, the device threshold voltage (VTh) can also be modulated by varying the para-substituent of the monolayers such that the molecule bearing electron-withdrawing groups would significantly shift the VTh towards the positive region for the enhancement mode device operation, in which the effect has been quantified by density functional theory calculations. These findings reveal explicitly the efficient modulation of the InAs nanowires' electronic transport properties via ArS(-)-based molecular monolayers, which further elucidates the technological potency of this ArS(-) surface treatment for future nanoelectronic device fabrication and circuit integration.
authors.forename: Ho-Yuen
authors.initials: HY
authors.lastname: Cheung
authors.forename: SenPo
authors.initials: S
authors.lastname: Yip
authors.affiliation: ∥State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, P.R. China.
authors.forename: Ning
authors.initials: N
authors.lastname: Han
authors.forename: Goufa
authors.initials: G
authors.lastname: Dong
authors.forename: Ming
authors.initials: M
authors.lastname: Fang
authors.forename: Zai-xing
authors.initials: ZX
authors.lastname: Yang
authors.affiliation: ⊥Cultivation Base for State Key Laboratory, Qingdao University, No. 308 Ningxia Road, Qingdao 266071, P.R. China.
authors.forename: Fengyun
authors.initials: F
authors.lastname: Wang
authors.forename: Hao
authors.initials: H
authors.lastname: Lin
authors.forename: Chun-Yuen
authors.initials: CY
authors.lastname: Wong
authors.forename: Johnny C
authors.initials: JC
authors.lastname: Ho
keywords: InAs nanowires; aromatic thiol; electrical properties; mobility; molecular monolayers; threshold voltages