Elemental Composition, Topography and Wettability of PbxSn1 - xS Thin Films

Abstract

Ternary semiconductor materials have attracted much attention because of their potential application in photonic devices [1]. PbS SnS materials are promising materials in photovoltaic, infrared detection [2]. In addition, by using tin sul de compounds in photovoltaic structures the production costs of solar cells would decrease, because the materials involved are cheap, nonstrategic, and abundant in nature. As we know, the fabrication involves many steps, using di erent deposition methods. It is usually a time consuming and expensive process. In general, the nature of the surface of any material plays a crucial role in device fabrication. The surface energy of the adhesive material and the contact angle are the characteristics of molecular adhesion. Su cient wetting is necessary for a good contact adhesion. The larger the wetting, and hence, the smaller contact angle, the stronger the adhesion and the greater the possibility for the adhesive material lling the pores on the surface of the substrate. If the adhesive material in the coating formed air bubbles between the adhesive and the substrate, then these areas are potentially breaking the adhesive bonds in some places as a result of the applied external force. Therefore, the performance of the junction and the cell depends critically on composition, structure and morphology of the absorber surface, whereas local inhomogeneity, chemical composition and surface morphology determine surface wettability. The wettability interferes with adhesion absorber surface [3] (and, in turn, with performance of the junction), which in turn in uences solar cell energy conversion e ciency. Lokhande et al. [4] and Roh et al. [5] propose to use contact angle measurements as a diagnostic method to determine the quality of CuInS2 absorbers without forming an actual solar cell.