Investigation of Structural, Electrical and Triboelectric Properties of TiO2 Thin Films

The growth of micro or nanosystems and the need to make them autonomous are increasing day by day. Many studies are being carried out to solve the energy needs resulting from this increase. It is considered a promising solution, especially for electrostatic mechanical energy harvesters (E-MET), the internet of things (IoT), and wearable devices. The triboelectric based electret generator (TENJ), which belongs to the electrostatic mechanical energy harvesters (E-MET) family, is far beyond the original energy harvesting device in terms of application, and it has various fields such as self-powered nanosystems, self-operated electrochemistry, and human-machine interaction. The basic working mechanism of TENJs involves combining contact electrification and electrostatic induction while converting mechanical energy into electrical energy. In addition to the advantages of low cost, diverse construction, stable output, and high energy conversion efficiency, TENJs can also be characterized by environmental friendliness and a wide application range. This thesis is including that, TiO2 growth on Si-substrate by the magnetron sputtering method was investigated with varying sputtering power (50W, 75W, and 100W), sputtering pressure (5mTorr, 8mTorr, 10mTorr, 12mTorr, 15mTorr), partial pressure of O2 (%5, %10, %15) and thickness (5nm, 10nm, 25nm, 50nm, 75nm, and 100nm) parameters. The best triboelectric material performance was demonstrated by a 100nm thick TiO2 thin film annealed at 900°C under a partial pressure of %10 O2 at 75W power and 10mTorr pressure. This thesis has recently focused on the TiO2 semiconductor material by developing new materials for TENJs as active layers and device configurations to elucidate their working mechanisms. It used a polyethylene terephthalate/indium tin oxide (PET/ITO) film as a positive-type friction layer for the TENJs for efficient collection by the contact separation mode. The TENJ operating in the TiO2-based contact separation mode, obtained with different production parameters, has an output voltage of 55 V with excellent mechanical stability and the highest peak power density (27μW.m–2).