Metal Oxide ZnO ZnO is promising earth-abandant n-type metal oxide semiconductor that is widely used for opto-electrical devices. It has direct band-gap of 3.3 eV with favorable band edge for absorbing light, so it is used at pec, sensor, and solar cell devices. We have technique to simply synthesize well-aligned ZnO nanorod array using hydrothermal method. First, a 50 nm ZnO film was deposited on a FTO glass as a seed layer for hydrothermal growth. At basic condition, ZnO nanorod grow along ZnO[0001] direction on seed layer. It can be patterned, and has high electric conductivity. ZnO nanorod array can be used easily as a scaffold. We made variable junction with ZnO nanorod array, and other material, and make efficient devices. TiO2 TiO2 has been considered a promising material for optoelectrical applications including photovoltaic including photovoltaic cells, optical sensors, and dye-sensitized solar cells, because it is a low cost material with as appropriate bandgap, high photocatalytic activity, and chemical durability. TiO2 has three major crystalline polymorphs: rutile (tetragonal), anatase (tetragonal), and brookite (orthorhombic). Rutile is a stable phase whereas anatase and brookite are metastable phases that can be transformed to rutile when annealed. Most previous studies have focused on the anatase and rutile phases, while brookite TiO2 has scarcely been studied because the brookite phase rarely exists in nature and is difficult to synthesize. Our research team fabricated high-quality single crystalline brookite TiO2 nanoarrays with facile hydrothermal method. This brookite TiO2 nanoarrays shows better photoelectrochemical properties and stability. WO3 WO3 is a well-known wide-bandgap semiconductor, which has high conductivity and extensive surface area. Therefore, it has been studied for use in many important applications, including electrochromic windows, optical devices, gas sensors, and photocatalysts. Our team can fabricate WO3 nanowires with thermal evaporation method, so the products have large surface area and high crystallinity. Additionally, due to their inherent surface roughness, tungsten oxide nanowire arrays have been used in the fabrication of superhydrophobic/philic surfaces with controllable wetting properties. In general, the ability to control the wetting properties provides a multi-functionality of the surface, such as non-wetting, self-cleaning, anti-fogging, and anti-freezing properties.