Analytical Model for the Optical Functions of Indium Gallium Nitride with Application to Thin Film Solar Photovoltaic Cells

TL;DR

This paper develops an analytical model for the optical properties of indium gallium nitride thin films, aiding the characterization of materials for thin film solar cells using spectroscopic ellipsometry.

Contribution

It introduces a Kramers-Kronig consistent analytical model with Gaussian oscillators for InxGa1-xN films, enabling detailed optical property extraction.

Findings

Successful modeling of dielectric functions of InxGa1-xN films

Correlation between SEM microstructure and optical properties

Model applicability to other InxGa1-xN films

Abstract

This paper presents the preliminary results of optical characterization using spectroscopic ellipsometry of wurtzite indium gallium nitride (InxGa1-xN) thin films with medium indium content (0.38<x<0.68) that were deposited on silicon dioxide using plasma-enhanced evaporation. A Kramers-Kronig consistent parametric analytical model using Gaussian oscillators to describe the absorption spectra has been developed to extract the real and imaginary components of the dielectric function ({\epsilon}1, {\epsilon}2) of InxGa1-xN films. Scanning electron microscope (SEM) images are presented to examine film microstructure and verify film thicknesses determined from ellipsometry modelling. This fitting procedure, model, and parameters can be employed in the future to extract physical parameters from ellipsometric data from other InxGa1-xN films.