Effect of Indium Fractional Content on Structural, Roughness and Spectroscopic Characteristics of CuInS2 Thin Films prepared by Electron beam Epitaxy

Abstract

Electron beam epitaxy (EBE) is a highly controlled physical vapor deposition technique used to grow high-quality copper-indium-sulfur (Cu-In-S) ternary thin films on silicon substrates for heterojunction solar cells. This method employs a high-energy electron beam to evaporate pure Cu, In, and S sources in a high-vacuum environment, enabling precise stoichiometric control and epitaxial growth. The heated silicon substrate (300–500°C) promotes crystallinity and adhesion, while independent evaporation rate monitoring ensures optimal film composition. In this work, CuInS₂ thin films were deposited on silicon substrates by electron beam epitaxy (EBE) to fabricate anisotropic heterojunctions for solar cells technology. The structural, roughness and spectroscopic characteristics of these heterojunctions were determined, studied and analyzed as functions of the partial fractions of copper (Cu) and indium (In) in the ternary compound samples.