title: Influence of water content in mixed solvent on surface morphology, wettability, and photoconductivity of ZnO thin films.
abstract: ZnO thin films have been synthesized by means of a simple hydrothermal method with different solvents. The effect of deionized water content in the mixed solvents on the surface morphology, crystal structure, and optical property has been investigated by scanning electron microscopy, X-ray diffraction, and UV-Vis spectrophotometer. A large number of compact and well-aligned hexagonal ZnO nanorods and the maximal texture coefficient have been observed in the thin film, which is grown in the mixed solvent with x = 40%. A lot of sparse, diagonal, and pointed nanorods can be seen in the ZnO thin film, which is grown in the 40-mL DI water solution. The optical band gap decreases firstly and then increases with the increase of x. Reversible wettability of ZnO thin films were studied by home-made water contact angle apparatus. Reversible transition between hydrophobicity and hydrophilicity may be attributed to the change of surface chemical composition, surface roughness and the proportion of nonpolar planes on the surface of ZnO thin films. Photocurrent response of ZnO thin films grown at different solvents were measured in air. The response duration of the thin film, which is grown in the solvent with x = 40%, exhibits a fast growth in the beginning but cannot approach the saturate current value within 100 s. The theoretical mechanism for the slower growth or decay duration of the photocurrent has been discussed in detail.
authors.affiliation: School of Physics and Material Science, Anhui University, Hefei 230039, China ; School of Electronic and Information Engineering, Hefei Normal University, Hefei 230601, China.
authors.forename: Min
authors.initials: M
authors.lastname: Zhao
authors.affiliation: School of Electronic and Information Engineering, Hefei Normal University, Hefei 230601, China.
authors.forename: Fengjiao
authors.initials: F
authors.lastname: Shang
authors.affiliation: School of Physics and Material Science, Anhui University, Hefei 230039, China ; School of Electronic and Information Engineering, Hefei Normal University, Hefei 230601, China ; National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China.
authors.forename: Jianguo
authors.initials: J
authors.lastname: Lv
authors.affiliation: School of Electronic and Information Engineering, Hefei Normal University, Hefei 230601, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Song
authors.affiliation: School of Electronic and Information Engineering, Hefei Normal University, Hefei 230601, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.affiliation: School of Electronic and Information Engineering, Hefei Normal University, Hefei 230601, China.
authors.forename: Zhitao
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: School of Physics and Material Science, Anhui University, Hefei 230039, China.
authors.forename: Gang
authors.initials: G
authors.lastname: He
authors.affiliation: School of Physics and Material Science, Anhui University, Hefei 230039, China.
authors.forename: Miao
authors.initials: M
authors.lastname: Zhang
authors.affiliation: School of Physics and Material Science, Anhui University, Hefei 230039, China.
authors.forename: Xueping
authors.initials: X
authors.lastname: Song
authors.affiliation: School of Physics and Material Science, Anhui University, Hefei 230039, China.
authors.forename: Zhaoqi
authors.initials: Z
authors.lastname: Sun
authors.affiliation: School of Electronic and Information Engineering, Hefei Normal University, Hefei 230601, China.
authors.forename: Yiyong
authors.initials: Y
authors.lastname: Wei
authors.affiliation: National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China.
authors.forename: Xiaoshuang
authors.initials: X
authors.lastname: Chen
keywords: Chemical synthesis; Electrical conductivity; Electron microscopy; Thin films