Characterization of ZnO thin films grown by linear sweep voltammetry

By using a linear sweep voltammetry technique, ZnO nanostructured thin films with average diameter of less than 100 nm were synthesized from nitrate aqueous solution on FTO substrate. The effects of electrodeposition parameters such as sweep rate and number of scans were investigated by scanning electron microscopy (SEM), X-ray diffraction and ultraviolet visible transmission spectroscopy. The deposited films show hexagonal Zincite structure and a high transmittance up to 85% in the near infrared and part of the visible region. The results reveal that the electrodeposition parameters have significant influence on the morphology, the average diameter and the shape of ZnO Crystallite. In addition, the optical properties of grown films were strongly affected by the sweep rate parameter.

I. Introduction

Zinc oxide (ZnO) is a well-known n-type semiconductor, with a large band gap (3.36eV) and large exciton binding energy (60 meV) at room temperature [1]. Because of these characteristics, ZnO has attracted global interest for potential applications, for instance optoelectronic [2], catalysis [3], sensors [4] and solar cells [5]. In solar cells, ZnO is widely used as a buffer layer for system based on Cu(In, Ga)Se2 and CTZS [6]. Moreover, ZnO is used in several hetero junction systems such as CU₂ O/ZnO [7] and CdTe/ZnO [8].