2021 Volume 72 Issue 1 Pages 50-56
The ZnO vertical nanowires and layers were prepared by electrodeposition in aqueous solutions containing zinc nitrate hydrate and zinc chloride hydrate with total Zn concentration set at 0.8, 8, and 80 mmol/L with the zinc chloride hydrate molar ratio of 0 - 10 mol%. Their electrochemical, structural, and electrical characteristics were investigated with electrochemical measurements including a Mott-Schottky plot, X-ray diffraction, SEM observation, and optical transmission spectra measurements. The <0001>-oriented ZnO nanowires with 3.3 eV bandgap energy and <0001>-oriented ZnO layers with 3.4 eV bandgap energy were prepared in 0.8, 8, and 80 mmol/L solutions. The growth rate for the ZnO nanowires was 44 nm h－1 at the total Zn concentration of 0.8 mmol/L and zinc chloride molar ratio of 0.1 mol%（0.8 mmol/L - 0.1 mol%）increased to 290 nm h－1 at 8 mmol/L - 0.1 mol%. The ZnO nanowires width increased from 40 nm at 0.8 mmol/L - 0 mol% to 285 nm at 8 mmol/L - 10 mol% with increases in both the total Zn concentration and zinc chloride molar ratio. The carrier concentration of ZnO nanowires and layers increased to maximum values at around 0.1～1 mol% with the increase in the zinc chloride molar ratio, and decreased at 10 mol%. The change affected the growth rate. Also, the change in the width of the ZnO nanowires and layer was related to the zinc chloride molar ratio because of change in the ZnO crystal growth direction.
