• Novak, K. V.
• Nashchekina, Olga
• Budnik, A. V.
• Doroshenko, A. N.
• Rogacheva, E. I.

Abstract

The objects of the present study are thin films with thicknesses d = 45-620 nm prepared by thermal evaporation in vacuum from a single source, using undoped p- and n-type Bi₂Te₃ polycrystals with different stoichiometry (60.0 and 62.8 at. % Te, respectively) as a charge, and subsequent condensation on glass substrates at 500 K. The temperature dependences of the Hall coefficient Rн, electrical conductivity σ, and Hall charge carrier mobility μн of thin films were obtained in the range 77-300 K. It was found that the films had the same type of conductivity as the initial polycrystals in the entire temperature range studied and, like in the initial crystals, σ and μн decreased with increasing temperature. The exponents ν in the μн(T) dependences for the bulk polycrystals were larger than those for the films and increased with increasing d. In contrast to the p-type bulk polycrystals, Rн of the p-type films decreased under increasing temperature. In the n-type Bi₂Te₃, Rн decreased with temperature for both thin films and bulk crystals, however, the character of the Rн(T) dependences for the crystals and films differed. The decrease in Rн with temperature before the range of intrinsic conductivity in all thin films is attributed to the existence of donor and acceptor defect states.

Topics

• impedance spectroscopy
• mobility
• thin film
• glass
• glass
• defect
• electrical conductivity
• evaporation
• Bismuth