Improving the performance of UV photodiode detectors by changing the dimensions of ZnO nanorods

The manufactured UV photodiode is based on the heterogeneous bonding of zinc oxide and silicon nanorods. These nanorods with different dimensions were grown on a substrate of p-type silicon and by hydrothermal method. The dimensions of the nanorods was caused by reducing the concentration of the precursors under the same temperature and growth time, which led to a decrease in the diameter of the nanorods from 350 to 60 nm. Using SEM images, XRD, PL, UV–visible, Raman spectra and I–V characteristic curves of the samples under UV laser irradiation, their morphology, structural, optical characteristics, absorption rate and electrical properties were evaluated. A sample with the smallest dimensions showed the lowest dark current and the highest sensitivity at a bias voltage of −10 V, which is equal to $4.3\mu A$ and 48.441, respectively. These results showed that a favorable improvement has been made in the main parameters of UV photodiode detectors with smaller nanorods. By reducing the dark current and increasing the sensitivity of samples with a reduced dimension, UV photodiodes with optimal responses were.