Abstract
Bismuth telluride is a narrow bandgap compound semiconductor and has been used in thermoelectric coolers for decades. To prepare efficient thermoelectric microcoolers high-quality bismuth telluride thin films become essential. Bismuth telluride thin films are, in general, deposited at elevated temperatures to obtain crystalline microstructure with reasonable thermoelectric properties but rough film morphology. In this study an alternative approach has been presented to preserve good thermoelectricity as well as flat film morphology by preparing periodic BiTe multilayer structures at room temperature and post-thermal treatment at 200°C. Bi2 Te3 was identified to be the major compound phase existing in the annealed samples by X-ray diffraction analysis. Interestingly, the Seebeck coefficients and sheet resistance of the annealed BiTe multilayer samples showed an oscillatory behavior with increasing thermal annealing time. The oscillation of the thermoelectric power is speculated to be related to the confinement of electrons in a periodic potential well, which leads to the thickness-dependent oscillation in electron density and Seebeck coefficient of the annealed BiTe multilayer thin films. © 2007 The Electrochemical Society.