Thermoelectric and magnetotransport properties of Bi_1-xSb_x thin films and Bi/CdTe superlattices

The magnetotransport properties of Bi_1-xSb_x thin films (x = 0, 0.09 and 0.16) and Bi/CdTe superlattices have been determined by applying the quantitative mobility spectrum analysis (QMSA) and multicarrier fitting to the magnetic-field-dependent resistivities and Hall coefficients, using algorithms which account for the strong anisotropy of the mobilities. The experimentally derived electron and hole densities and mobilities are then used as the input to a nonparabolic and anisotropic band model that derives the thermal occupations and relaxation times for L-valley electrons and holes as well as T-valley and H-valley holes. This allows a calculation of the thermoelectric properties for comparison with experimental results. While the data for a Bi thin film and Bi/CdTe superlattices are reproduced quite well without any adjustable parameters, for Bi_1-xSb_x thin films a non-uniform doping profile must be assumed.