Fabrication of Microstructured thermoelectric Bi2Te3 thin films by seed layer assisted electrodeposition

Abstract

In this work, bismuth telluride (Bi2Te3) thin films have been fabricated on Bi2Te3/ITO substrates by constant potential electrochemical deposition at room temperature. Bi2Te3 seed layers with different thicknesses (2nm, 4nm and 6nm) were deposited onto ITO substrates using molecular beam epitaxy (MBE) method. The SEM images show that the morphology of Bi2Te3 thin films can be controlled not only by the deposition potential, but also the thickness of seed layer. Moreover, the morphologies of Bi2Te3 thin films with different thickness of seed layers tend to be similar and contain two-layer structure along the vertical direction after prolonged deposition time. Due to the two layers structure, Bi2Te3 thin films have shown different electrical conductivity performances. At room temperature, Bi2Te3 thin films with 4 nm-thick seed layer possess the maximum electrical conductivity value of 617.9 s cm-1.