Growth of thermoelectric Bi<inf>85</inf>Sb<inf>15</inf> alloy thin films and their characterization by XRD, TEM &amp; RBS

Bismuth and antimony are semimetals. The Bi(1-x)Sbx alloys (0.04<×<0.22) are found to show fair Seebeck coefficient suitable for thermoelectric applications. Bulk Bi85Sb15 alloy was prepared by the melt-quenching technique. The phase formation was confirmed by XRD. The thin films were prepared by the conventional flash evaporation technique to ensure stoichiometry and to avoid dissociation. The XRD, TEM and RBS studies were done for structural and compositional characterization of thin films. The results show that our method of preparation of bulk as well as thin films leads to no change in stoichiometry. The thicknesses of thin films as measured by the in-situ quartz crystal monitor and those evaluated from the RBS spectra agree well. The thermoelectric power measurements on thin films were made by the integral method and the data analyzed by the Jain-Verma theory to evaluate the power index in the energy dependent relaxation time, giving an idea about the nature of scattering. The detection of nature of scattering in the thin film material will help us to optimize the figure of merit and hence to enhance the thermoelectric properties.