MBE growth and thermoelectric properties of Bi2Te3 thin films

We have grown high quality Bi2Te3 thin films on CdTe(111)B substrates using MBE. Structural properties have been investigated using in-situ reflection high-energy electron diffraction (RHEED) and theta-2 theta X-ray diffraction analysis. They show that Bi2Te3 films on CdTe(111) grow along the (00.l) in the hexagonal cell with a layer-by-layer growth mode, resulting in a smooth surface, and an X-ray Bragg peak FWHM of 0.2 degrees. The thermopower and electrical conductivity of the stoichiometric Bi2Te3 films were similar to 200 mu V/K and 10(3) (Omega cm)(-1), respectively, comparable to the single crystal bulk values. We have observed the antisite defect effect in Te-rich Bi2Te3 films: excess Te occupies Bi lattice sites and behaves as an n-type dopant. Crystallinity and transport properties are strongly affected by non-stoichiometry.