UV-Enhanced Electrical Performances of ZnO:Ga Nanostructure Nanogenerators by Using Ultrasonic Waves

In this work, nanogenerator (NG) devices based on gallium-doped zinc oxide (ZnO) nanorods (NRs) (Ga-doped ZnO NRs) were triumphantly developed and explored by a simple fabrication process. All one-dimensional (1-D) nanostructures were hydrothermally grown on an indium-tin-oxide (ITO) substrate at a low temperature of 90 °C for 6 h. After field-emission scanning electron microscope (FE-SEM), X-ray diffractometer (XRD), and high-resolution transmission electron microscope (HR-TEM) measurement, a hexagonal wurtzite structure with good single crystallinity was exhibited, and a preferential growth with
${c}$
-axis direction was revealed. The optical properties of all samples were annealed at high temperature and explored through photoluminescence (PL) spectroscopy, displaying two different emission peaks, including ultraviolet (UV) and green emissions. The compositions of the NRs were also examined by an X-ray photoelectron spectroscopy (XPS) and an energy-dispersive X-ray (EDX) spectroscopy. As a result, the performance of ZnO NGs with Ga elements exhibits an outstanding improvement in electrical measurements compared with ZnO NGs. Furthermore, the output voltage and current of Ga-doped ZnO NG under UV irradiation were approximately 0.053 V and
$4.86\times10$
−6 A, respectively. It is attributed to produce numerous electrons by UV light and Ga dopant. The designed NG in this article may collect electrical energy in the people’s surroundings and has potential Internet of Thing applications (e.g., portable electronics, wireless devices, and implantable biomedical sensors).