In₂S₃ Thin Films via Open‐Air Chemical Vapor Deposition Using Indium‐Diethyldithiocarbamate: Deposition and Characterization

Abstract

Cadmium‐free materials for the buffer layer of thin‐film solar cells and their low‐cost manufacturing methods have been of great interest in the solar industry. In this study, diindium trisulfide (In2S3) is investigated as an alternative buffer layer material: In2S3 thin film was deposited at atmospheric pressure utilizing open‐air chemical vapor deposition (CVD). Indium‐diethyldithiocarbamate (In‐DDTC) is used as the only solid precursor. The deposition conditions, crystal structure, optical properties, and electrical properties of In2S3 thin films are studied. The solid source temperature is found to affect the morphology, whereas the substrate temperature affected the growth rate and the sulfur‐to‐indium ratio of the films. X‐Ray diffraction and Raman scattering measurements suggested that the prepared films consist of β‐In2S3 and show a strong (103)‐plane orientation under suitable deposition conditions. The films exhibited indirect and direct transitions around 2.0 eV and 2.7–2.8 eV, respectively. The thin films showed n‐type conduction, with the lowest resistivity of 28.6 Ω cm. Overall, In2S3 thin films prepared via open‐air CVD are promising alternative buffer layer materials, which are expected to contribute to the realization of low‐cost and environmentally friendly thin‐film solar cells.