A Study on the Properties of MgF 2 Antireflection Film for Solar Cells

Abstract

MgF 2 is a current material used for optical applications in the ultraviolet and deep ultraviolet range. Process variables for manufacturing MgF 2 thin film were established in order to clarify the optimum conditions for the growth of the thin film, dependant upon the process conditions, and then by changing a number of the vapor deposition conditions, substrate temperatures, and heat treatment conditions, the structural and optical characteristics were measured. Then, optimum process variables were thus derived. Nevertheless, modern applications still require improvement in the optical and structural quality of the deposited layers. In the present work, in order to understand the composition and microstructure of MgF 2 , single layers grown on a slide glass substrate using an Electron beam Evaporator (KV-660), were analyzed and compared. The surface substrate temperature, having an effect on the quality of the thin film, was changed from 200°C to 350°C at intervals of 50°C. The heat treatment temperature, which also has an effect on the thin film, was changed from 200°C to 400°C at intervals of 50°C. The physical properties of the thin film were investigated at various fabrication conditions, such as the substrate temperature, the heat treatment temperature, and the heat treatment time, by X-ray diffraction, and field emission-scanning electron microscopy.