INFLUENCE OF THE ULTRASONIC VIBRATION ON CHEMICAL BATH DEPOSITION OF ZnS THIN FILMS

Abstract

Chemical bath deposition (CBD) and ultrasonic chemical bath deposition (US-CBD) of ZnS thin films from NH 4 OH/SC ( NH 2)2/ ZnSO 4 solutions have been studied. The influence of the ultrasonic vibration on properties of ZnS thin films has been investigated. The growth rate, structure, and properties of ZnS thin film deposited by different CBD techniques were studied using X-ray diffractometer (XRD), scanning electron microscopy (SEM), and atomic force microscope (AFM). The results show that the growth rate of US-CBD is slower than that of CBD. The XRD analysis of as-deposited ZnS films shows that the films are both cubic ZnS structure and the crystallinity of US-CBD ZnS film is higher than that of CBD ZnS film. SEM studies indicate that adhesion particles on the US-CBD ZnS surface are fewer than that on the CBD ZnS surface. Moreover, the film prepared by US-CBD is homogeneous and with high compactness. The rms roughness (R rms ) value of CBD ZnS film is higher than that of US-CBD. Transmission measurement shows that the optical transmittance of US-CBD ZnS is higher than that of CBD ZnS , and the optical transmittance is above 90% when the wavelength is over 470 nm. The band gap (Eg) values of the films deposited by CBD and US-CBD are 3.50 and 3.67 eV, respectively.