Hierarchical zinc oxide nanobrushes ultraviolet photodetector

Abstract

Abstract In order to synthesise hierarchical zinc oxide (ZnO) nanomaterials with a high surface‐to‐volume ratio, a well‐controlled multistage hydrothermal method was developed. Hierarchical ZnO nanobrushes (ZNBs) built from initial mono‐morphological nanomaterials, ZnO nanowires (ZNWs), and ZnO nanoplates (ZNPs) were developed using sequential nucleation and growth following a hydrothermal process. Hierarchical nanomaterials which are comprised of one‐dimensional (1D) nanowire building blocks were obtained via a zinc ion source (zinc nitrate) during the second growth phase. In comparison to their first mono‐morphological equivalents, the hierarchical nanomaterials which were grown showed improved ultraviolet (UV) detection, as well as improved sensitivity (∼104), an ultra‐fast response time (235 ms), and a good recovery time (310 ms). Improvements to the response and recovery times were a result of distinct nanojunction barrier‐dominated resistance. Moreover, the enhanced sensitivity of the ZNB photodetector (PD) was because of the reduced dimensionality and the ultrahigh surface‐to‐volume ratio. This work lays the groundwork for lower‐cost, larger‐scale, and lower‐temperature production of high‐performance nanostructured ZnO‐based PDs on transparent and flexible substrates.