Structural Evaluation of Bi 2 Te 3 Thin Films Prepared by Hydrogen-Argon Mixing Sputtering

Abstract

We prepared bismuth telluride (Bi 2 Te 3 ) thin film using radio-frequency magnetron sputtering with different H 2 -Ar gas mixing ratios, and investigated the structural properties of the Bi 2 Te 3 thin films. The deposition rate of the thin films decreased as the mixing ratio was increased because tellurium atoms were lost from the films via the chemical reaction between the tellurium and hydrogen atoms. This phenomenon was supported with the results of the other analyses such as scanning electron microscopy (SEM), electron probe microanalyzer (EPMA), and X-ray diffraction method (XRD). The highest crystallinity was obtained at the H 2 -Ar gas mixing ratio of 5%. When the H 2 gas was introduced, the oxygen concentration near film surface decreased. Therefore, we conclude that the crystallinity and dense structure of Bi 2 Te 3 thin films improved by introducing an optimal amount of hydrogen gas in the sputtering deposition. It can be expected that the electrical conductivity of the thin films improves owing to the enhancement of electron transport.