Thermoelectric behaviour of (Bi0.5Sb0.5)(2)Te-3 semiconducting alloy thin films

The Jain-Verma theory has been applied to the thermoelectric data of vacuum flash-evaporated and annealed polycrystalline thin films of (Bi0.5Sb0.5)(2 )Te-3 alloys of different thicknesses to study the nature of principal carr ier scattering mechanism and also to know the extent of other scattering me chanisms, simultaneously. It is found that the value of the energy dependen t scattering index parameter lies between -0.45 and -0.4. This indicates th at, even though the principal scattering mechanism in the films is the norm al lattice scattering, other scattering like 'impurity' scattering, surface scattering and grain boundary scattering may be present. (C) 2001 Elsevier Science Ltd. All rights reserved.