Bismuth antimony telluride thin films with unique crystal orientation by two-step method

P-type bismuth antimony telluride thin films have been prepared by flash evaporation and a subsequent two-step synthesis method of homogeneous electron beam (EB) irradiation and thermal annealing. EB irradiation of the thin films was performed in a N-2 atmosphere at room temperature and an acceleration voltage of 0.17 MeV. Thermal annealing was performed at 300 degrees C for 1 h under Ar/H-2 (95/5%). Thin films prepared using the two-step method exhibit a unique crystal orientation that provides improved electrical conductivity and an improved Seebeck coefficient. With an EB irradiation dose of 0.43 MGy, the power factor of the thin films reached 38.4 mu W/(cm.K-2).Thermal conductivity was calculated using a phonon transport model and the Wiedemanne-Franz law, providing a dimensionless figure of merit (ZT). The ZT was expected to enhance significantly by a two-step method compared with alternate synthesis techniques. (C) 2016 Elsevier B.V. All rights reserved.