The optimization of the thermal co-evaporation deposition process for n-type bismuth telluride (Bi2Te3) thin films deposited onto polyimide substrates and intended for thermoelectric applications is reported. The influence of deposition parameters (evaporation rate and substrate temperature) on film composition and thermoelectric properties was studied for optimal thermoelectric performance. Energy-dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Raman spectroscopy confirmed the formation of Bi2Te3 thin films. Seebeck coefficient (up to 250 mu V K-1), in-plane electrical resistivity m), carrier concentration (3x10(19)-20x10(19) cm(-3)) and Hall mobility (80-170 cm(2)V(-1)s(-1)) were measured at room temperature for selected Bi2Te3 samples. (C) 2009 Elsevier B.V. All rights reserved.