title: Laser modified ZnO/CdSSe core-shell nanowire arrays for Micro-Steganography and improved photoconduction.
abstract: Arrays of ZnO/CdSSe core/shell nanowires with shells of tunable band gaps represent a class of interesting hybrid nanomaterials with unique optical and photoelectrical properties due to their type II heterojunctions and chemical compositions. In this work, we demonstrate that direct focused laser beam irradiation is able to achieve localized modification of the hybrid structure and chemical composition of the nanowire arrays. As a result, the photoresponsivity of the laser modified hybrid is improved by a factor of ~3. A 3D photodetector with improved performance is demonstrated using laser modified nanowire arrays overlaid with monolayer graphene as the top electrode. Finally, by controlling the power of the scanning focused laser beam, micropatterns with different fluorescence emissions are created on a substrate covered with nanowire arrays. Such a pattern is not apparent when imaged under normal optical microscopy but the pattern becomes readily revealed under fluorescence microscopy i.e. a form of Micro-Steganography is achieved.
authors.affiliation: Department of Physics, 2 Science Drive 3, National University of Singapore, 117542, Singapore.
authors.forename: Junpeng
authors.initials: J
authors.lastname: Lu
authors.affiliation: Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 3 Research Link, 117602, Singapore.
authors.forename: Hongwei
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Physics, 2 Science Drive 3, National University of Singapore, 117542, Singapore.
authors.forename: Minrui
authors.initials: M
authors.lastname: Zheng
authors.affiliation: Department of Physics, 2 Science Drive 3, National University of Singapore, 117542, Singapore.
authors.forename: Hongji
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Physics, 2 Science Drive 3, National University of Singapore, 117542, Singapore.
authors.forename: Sharon Xiaodai
authors.initials: SX
authors.lastname: Lim
authors.affiliation: Department of Physics, 2 Science Drive 3, National University of Singapore, 117542, Singapore.
authors.forename: Eng Soon
authors.initials: ES
authors.lastname: Tok
authors.affiliation: Department of Physics, 2 Science Drive 3, National University of Singapore, 117542, Singapore.
authors.forename: Chorng Haur
authors.initials: CH
authors.lastname: Sow