A High Sensitivity UV Photodetector With Inkjet Printed ZnO/Nanodiamond Active Layers

The single- and double-layered photodetectors based on ZnO and/or detonation nanodiamond (DND) have been developed via a sequential inkjet printing on the interdigital electrode platform using a diamond and zinc oxide precursor ink. The morphological structure of the deposited materials was visualized and analyzed by scanning electron microscopy and atomic force microscopy. The crystalline configuration and structural quality of ZnO and nanodiamond were investigated by X-ray diffraction and Raman spectroscopy. The response, response time, and recovery time were measured for different UV wavelengths (365, 385, and 405 nm), light intensities, temperatures, and bias voltages. The ZnO/DND structure shows more than ten times higher response and faster reactivity in comparison with a single-layered photodetector. Photoresponsivity of the double-layered photodetector (ZnO/DND) is 0.35 A $\cdot \,\,\text{W}^{ {-1}}$ , whereas bare ZnO is about 0.039 A $\cdot \,\,\text{W}^{{-1}}$ . The interaction between UV light and ZnO/DND grains was investigated by two dimensional Silvaco TCAD simulation.