title: Shape-Controlled Deterministic Assembly of Nanowires.
abstract: Large-scale, deterministic assembly of nanowires and nanotubes with rationally controlled geometries could expand the potential applications of one-dimensional nanomaterials in bottom-up integrated nanodevice arrays and circuits. Control of the positions of straight nanowires and nanotubes has been achieved using several assembly methods, although simultaneous control of position and geometry has not been realized. Here, we demonstrate a new concept combining simultaneous assembly and guided shaping to achieve large-scale, high-precision shape controlled deterministic assembly of nanowires. We lithographically pattern U-shaped trenches and then shear transfer nanowires to the patterned substrate wafers, where the trenches serve to define the positions and shapes of transferred nanowires. Studies using semicircular trenches defined by electron-beam lithography yielded U-shaped nanowires with radii of curvature defined by inner surface of the trenches. Wafer-scale deterministic assembly produced U-shaped nanowires for >430,000 sites with a yield of ∼90%. In addition, mechanistic studies and simulations demonstrate that shaping results in primarily elastic deformation of the nanowires and show clearly the diameter-dependent limits achievable for accessible forces. Last, this approach was used to assemble U-shaped three-dimensional nanowire field-effect transistor bioprobe arrays containing 200 individually addressable nanodevices. By combining the strengths of wafer-scale top-down fabrication with diverse and tunable properties of one-dimensional building blocks in novel structural configurations, shape-controlled deterministic nanowire assembly is expected to enable new applications in many areas including nanobioelectronics and nanophotonics.
authors.forename: Yunlong
authors.initials: Y
authors.lastname: Zhao
authors.forename: Jun
authors.initials: J
authors.lastname: Yao
authors.affiliation: State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology , Wuhan 430070, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Xu
authors.forename: Max N
authors.initials: MN
authors.lastname: Mankin
authors.affiliation: CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China , Hefei, Anhui 230027, China.
authors.forename: Yinbo
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China , Hefei, Anhui 230027, China.
authors.forename: Hengan
authors.initials: H
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology , Wuhan 430070, China.
authors.forename: Liqiang
authors.initials: L
authors.lastname: Mai
authors.affiliation: State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology , Wuhan 430070, China.
authors.forename: Qingjie
authors.initials: Q
authors.lastname: Zhang
authors.forename: Charles M
authors.initials: CM
authors.lastname: Lieber
keywords: Silicon nanowires; bioelectronics; elastic deformation; field-effect transistors; nanoelectronics; nanowire arrays