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CdS/ZnO Core/Shell Nanowire‐Built Films for Enhanced Photodetecting and Optoelectronic Gas‐Sensing Applications
Author(s) -
Yang Zheng,
Guo Linjuan,
Zu Baiyi,
Guo Yanan,
Xu Tao,
Dou Xincun
Publication year - 2014
Publication title -
advanced optical materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.89
H-Index - 91
ISSN - 2195-1071
DOI - 10.1002/adom.201400086
Subject(s) - materials science , photodetector , nanowire , optoelectronics , heterojunction , photosensitivity , fabrication , light intensity , visible spectrum , nanotechnology , optics , pathology , medicine , alternative medicine , physics
Uniform CdS/ZnO core/shell nanowires are hydrothermally synthesized using a two‐step process and assembled into a photodetector and a NO 2 optoelectronic sensor for the first time. The corresponding photodetector exhibits a fast, reversible, and stable optoelectronic response with a rise time of ∼26 ms, a decay time of ∼2.1 ms and a stability of over 5 months. The remarkable photosensitivity and fast photoresponse are attributed to the formation of a heterojunction structure between CdS and ZnO, which greatly inhibits the recombination of photoinduced electrons and holes. The CdS/ZnO core/shell nanowires also show an excellent visible‐light‐activated gas sensing performance towards ppb‐level NO 2 at room temperature. The responses range from 6.7% to 337% toward NO 2 concentrations of 5 to 1000 ppb. It is found that the sensitivity of the NO 2 sensor is dependent on the illuminated light intensity with a maximum value at 0.68 mW/cm 2 . The sensing mechanisms of the CdS/ZnO nanowires under visible‐light irradiation and the influence of light intensity are also discussed. The present CdS/ZnO core/shell nanowire not only benefits the fabrication of efficient photodetectors, but also makes the instant, optically controlled sensing of ppb‐level NO 2 gas possible.