Chiao Yen Wang1 Chuan-Pu Liu1

1, National Cheng Kung University, Tainan, , Taiwan

Triboelectric nanogenerators(TENGs) have been intensively studied due to their simple device structures, high output voltages, and high energy conversion efficiency. The use of environmental triggers, such as friction, vibration, and deflection, serve as mechanical sources to power TENGs. In addition to these advantages, materials chosen for TENGs are not limited to wurtzite structures. General materials, including dielectric and polymer materials, are also commonly seen in TENGs, which largely broadens the application prospects, compared to the conventional semiconductor devices.
Generally, two materials with different tribopolarity result in a potential difference upon contact, leading to a contacted-induced charge transfer process, which is known as the basic mechanism of TENGs. The material structures fabricated can vary from nanowires to thin films. Recently, much attention paid to the research of TENGs focused on the device structure modification and the use of different materials. Here, we develop a simple structure based on nonpolar ZnO thin film. It has been shown that nonpolar facet of semiconductor has a huge impact on piezotronic effect of nanowire-based devices. Our work indicated that the nonpolar facet, or textured surface of ZnO thin film, can enhance the induced charges, which further increases the output power of TENG, compared to the same material under polar facet. The obliquely aligned ZnO thin film is grown by home-made magnetron sputtering. And the texture characteristics are carefully examined through XRD,SEM, and TEM. The physical mechanism is systematically investigated. To the best of our knowledge, this work provides the first evidence of how the nonpolar ZnO thin film improves the output power of TENGs.