Zinc Interstitial Rich ZnO Honeycomb Nanostructures for Deep UV Photodetection

Abstract

Pristine ZnO nanostructures (NSs) are less sensitive to deep UV radiations, which restrict their usage to near UV region only. In order to extend its usability in deep UV region; Zn interstitial rich honeycomb (HC) NSs of ZnO is developed. The device shows remarkably high photoresponsivity of 1150 A W−1 in deep UV region (λ = 254 nm). Additionally, enhanced deep UV photosensitivity is observed and can be attributed to the incorporation of Zn ions in ZnO lattice and large surface to volume ratio of HC NSs. Furthermore, in dark conditions, the width of the depletion region is comparable to the thickness of HC NSs (20 nm) that results in complete depletion of charge carriers in NSs, which results in significant reduction in dark current. Moreover, HC NSs are provided continuous conduction path which eliminates the potential barrier forming at the NSs interfaces, resulting in efficient charge transportation. The measured photocurrent to dark current ratio is as large as ≈6 orders of magnitude. Such large photosensitivity in the deep UV region of electromagnetic spectrum makes these devices a promising candidate for development of deep UV photo-detectors for commercial applications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim