Aligned arrays of CdS nanotubes for high-performance fully nanostructured photodetector with higher photosensitivity

Abstract

We report a novel and simple method to fabricate a high-sensitivity fully nanostructured photodetector by using CdS nanotubes (NTs) aligned arrays as active layer and Ag nanowires (NWs) transparent film as electrodes. The assembly of highly ordered and aligned CdS NTs arrays is obtained by a simple modified contact printing process. A fully nanostructured photodetector is fabricated by transferring the electrodes produced by Ag NWs network on the aligned CdS NTs arrays substrate, such that the aligned CdS NTs arrays as active layer are in contact with Ag NWs network as transparent electrodes. The resulting photodetector exhibits lower dark currents (<5 nA) and a higher photoresponse ratio (Ilight/Idark ≈ 219, 321) than that based on aligned arrays of CdS NWs, and its photosensitivity characteristics are even comparable to those of single nanostructure-based devices. In addition, the comparative studies of aligned NTs-based photodetetor in air and vacuum are investigated. The effects of the oxygen molecules on the photocurrent, dark current, rise time and decay time are investigated in details. This research may pave a way for large-scale fabrication of high performance and low cost nanostructured photodetectors for industrial applications.