ZnO film is of great interest for short-wavelength optoelectronic application because ZnO semiconductor with a wide band gap of 3.34eV has a large exciton binding energy of 60meV at room temperature. At present

there have been many different techniques used to prepare nanocrystalline ZnO films such as molecular beam epitaxy

vapor phase deposition

and pulsed laser deposition.In this paper nanocrystalline ZnO films have been grown by a simple method of cathodic electrodeposition. Preparation of ZnO films using this method presents several advantages such as relatively high deposition rate

low deposition temperature

and low equipment cost. Cathodic electrodeposition has been widely used to deposit ZnO micrometer size particles

while little has been reported on the deposition of ZnO nanoparticles by cathodic electrodepo sition on Si substrate. In this paper dimethylsulfoxide (DMSO) solutions containing ZnCl

2

is introduced to get OH free ZnO films. Furthermore Si wafers were used as the substrates

which is of considerable interest to the optoelectronic integration. Deposition is carried out in DMSO solutions containing ZnCl

2

with different concentration from 0.01mol/L to 0.05mol/L on Si substrates at room temperature. The grown films were characterized by means of ex situ techniques:X-ray diffraction

atom force microscopy

infrared spectroscopy and photoluminescence spectroscopy. The effects of ZnCl

2

concentration on the structural and optical properties of the films have been studied. The mean grain size of the samples

which increases with the increase of ZnCl

2

concentration are 9.8

10.4 and 14.5nm

respectively. The photoluminescence spectra of all the samples show two distinct features:strong ultraviolet emission lines from ZnO free exciton and negligibly weak green emission band around 510nm

which is from deep level defect emission associated with oxygen vacancies in the ZnO lattice.The exciton emission dominated in the photoluminescence spectra. In conclusion

nanocrystalline ZnO films have been fabricated by cathodic electrodeposition on Si substrates from DMSO ZnCl

2

electrolytes. The results indicate that this method is a promising way to prepare nanocrystalline ZnO films.