Composition-Dependent Characterization of Sb₂Te₃ Thin Films Prepared by Ion Beam Sputtering Deposition

The optimization of ion beam sputtering deposition process for Sb₂Te₃ thin films deposited on BK7 glass substrates is reported. The influence of composition ratio on the thermoelectric properties is investigated. X-ray diffraction shows that the major diffraction peaks of the films match with those of Sb₂Te₃. Hall effect and Seebeck coefficient measurement reveal that all the samples are of p-type. The Sb₂Te₃ thin films exhibit the Seebeck coefficient of 190 μVk^-1 and the electrical conductivity of 1.1×10³ Scm^-1 when the atomic ratio of Sb to Te is 0.65. Carrier concentration and motility of the films increase with the increasing atomic ratio of Sb to Te. The Sb₂Te₃ film with a maximum power factor of 2.26×10^-3 Wm^-1K^-2 is achieved when annealed at 400°C. Raman measurement shows that the main peaks are at about 120 cm^-1, 252 cm^-1and 450 cm^-1, in agreement with those of V-VI compound semiconductors.