Influence of Refresh Hydrothermally Grown ZnO Nanorods for Vibration Sensing Application

This research report investigates the effect of fabrication methodology in the sensitivity performance of the ZnO (Zinc Oxide)-based piezoelectric vibration sensor. For that, two types of synthesising techniques, namely, normal hydrothermal (H) method and refresh hydrothermal (R) methods were used for the growth of ZnO nanorods on rigid substrates. Insights into the structural and morphological properties of the active layer (ZnO) evidence the formation of hexagonal ZnO wurtzite structure and growth of 1D nanorods in both the samples. Optical analysis reveals a decreased bandgap and better crystal quality of the refresh hydrothermal method compared to the normal hydrothermal method. Electrical analysis confirms the formation of a p-n junction in both the devices. The fabricated vibration sensors were subjected to a vibration sensing experiment where a max output voltage of 2.52 V at 9 Hz resonant frequency was recorded for the R sensor. The sensitivity of the R sensor was similar to 3.54V/g which is 11% times higher than that of H.