Investigation of the optical properties of PLD-grown Bi<inf>2</inf>Te<inf>3</inf> and Sb<inf>2</inf>Te<inf>3</inf>

Abstract

The optical properties of Bismuth Telluride (Bi ₂ Te ₃ ) and Antimony Telluride (Sb ₂ Te ₃ ) thin films grown using pulsed laser deposition (PLD) were investigated. In one set of samples, the two materials were grown, on n-Si substrates, with growth temperatures ranging from 25 to 450°C. In the second set, the films were deposited on microscopic glass slides at 150 °C. The optical properties were studied using Ultra Violet-Visible (UV-Vis) and Fourier Transform Infrared (FTIR) spectroscopy techniques. Absorbance spectra were obtained using UV-Vis spectroscopy, while transmittance spectra were obtained using FTIR spectroscopy. From the FTIR spectra and employing the Tauc plots, the optical band gaps for both materials were obtained. The values of the optical band gaps for Bi ₂ Te ₃ are between 0.22-0.26 eV and for Sb2Te3 are between 0.19-0.28 eV.