Refractive Index of p-SnS Thin Films and its Dependence on Defects

TL;DR

This study investigates how defects influence the refractive index of p-type p-SnS thin films, revealing the relationship between optical properties and structural defects using dispersion models and ellipsometry.

Contribution

It demonstrates the dependence of the refractive index on defects and structural properties in p-SnS thin films, validated through Sellmeier and Wemple-Dedomenico models.

Findings

Refractive index follows Sellmeier dispersion model.

Ellipsometry improves dispersion data accuracy.

Defects and band-gap properties affect optical behavior.

Abstract

Tin sulphide thin films of p-type conductivity were grown on glass substrates. The refractive index of the as grown films, calculated using both Transmission and ellipsometry data were found to follow the Sellmeier dispersion model. The improvement in the dispersion data obtained using ellipsometry was validated by Wemple-Dedomenico (WDD) single oscillator model fitting. The optical properties of the films were found to be closely related to the structural properties of the films. The band-gap, its spread and appearance of defect levels within the band-gap intimately controls the refractive index of the films.