Study of the oxidation process of crystalline powder of In 2 S 3 and thin films obtained by Dr Blade method

TL;DR

This study investigates the oxidation process of In2S3 powders and thin films, analyzing the kinetics, structural changes, and optical properties during oxidation to understand phase transformations and band gap variations.

Contribution

It provides detailed insights into the oxidation mechanism of In2S3, including the identification of intermediate phases and the temperature-dependent band gap evolution.

Findings

Oxidation begins above 420°C.

Intermediate crystal phases form during oxidation.

Band gap varies from 1.94 eV to 3.72 eV.

Abstract

Good quality In2S3 films were grown by Dr Blade method from a powder synthesized in a chemical bath, and oxidized to obtain In2O3 films and films of intermediate composition. The oxidation process and kinetics are studied by means of thermogravimetric analysis, which shows complex phenomena. The study is completed by scanning electron microscopy and EDX measurements. X-ray diffraction and UV-visible spectroscopy results are also shown. The oxidation process begins significantly above 420 C, and it appears that at least one intermediate crystal phase takes place in the solid solution, suggesting that the replacement of sulfur by oxygen atoms occurs at different temperatures in the different crystallographic sites. The obtained samples show a band gap varying continuously between 1.94 eV and 3.72 eV.