Nanomechanical properties of Bi2Te3 thin films by nanoindentation

Abstract

In this study, the microstructural, morphological and nanomechanical properties of Bi2Te3 thin films are investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and nanoindentation techniques. The Bi2Te3 thin films were deposited on c-plane sapphire substrates using pulsed laser deposition (PLD) under the various helium gas pressures. The XRD results indicated that the Bi2Te3 thin films are textured with the c-axis preferentially oriented normal to the films surface. Both the grain size and surface roughness of the Bi2Te3 thin films exhibit an increasing trend with increasing the helium gas pressure. Furthermore, the hardness and Young\'s modulus of the Bi2Te3 thin films are measured by a Berkovich nanoindenter operated with the continuous contact stiffness measurements (CSM) mode were found to range from 2.92 +/- 0.12 to 4.02 +/- 0.14 GPa and from 106.31 +/- 0.63 to 127.46 +/- 9.21 GPa, respectively, when the helium gas pressure was increased from 2 x 10(-5) to 2 x 10(-3) Torr. (C) 2014 Elsevier B.V. All rights reserved.