Sn1-xBixO2 and Sn1-xTaxO2 (0 \leq x \leq 0.75): A first-principles study

TL;DR

This study uses first-principles calculations to analyze the structural, elastic, electronic, and optical properties of doped SnO2 compounds with Bi and Ta, revealing their transition to conductive oxides at certain doping levels.

Contribution

It provides the first calculation of elastic constants and stability for doped SnO2 compounds, and explores how doping affects their electronic and optical properties.

Findings

Band gap narrows with doping, disappearing at specific concentrations.

Doped compounds become conductive oxides at x ≤ 0.75.

Optical properties are characterized and compared with previous data.

Abstract

The structural, elastic, electronic and optical (x = 0) properties of doped Sn1-xBixO2 and Sn1-xTaxO2 (0 \leq x \leq 0.75) are studied by using the first-principles pseudopotential plane-wave method within the local density approximation. The independent elastic constants Cij and other elastic parameters of these compounds have been calculated for the first time. The mechanical stability of the compounds with different doping concentrations has also been studied. The electronic band structure and density of states are calculated and the effect of doping on these properties is also analyzed. It is seen that the band gap of the undoped compound narrowed with dopant concentration which disappeared for x = 0.26 for Bi doping and 0.36 for Ta doping. The materials thus become conductive oxides through the change in the electronic properties of the compound for x \leq 0.75 which may be useful for potential application. The calculated optical properties, e.g. dielectric function, refractive index, absorption spectrum, loss-function, reflectivity and conductivity of the undoped SnO2 in two polarization directions are compared with both previous calculations and measurements. Keywords: Doped SnO2; First-principles; Mechanical properties; Electronic band structure; Optical properties.