Effect of oxidation on thickness dependencies of thermoelectric properties in PbTe/mica thin films

• Published in: Thin solid films 2005-04, Vol.476 (2), p.391-395
• Main Authors: Rogacheva, E.I., Lyubchenko, S.G., Dresselhaus, M.S.
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electrical properties and measurements; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport phenomena in thin films and low-dimensional structures; Epitaxy; Exact sciences and technology; Galvanomagnetic and other magnetotransport effects (including thermomagnetic effects); Lead telluride; Oxidation; Physics; Thermoelectric effects
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2004.10.048

The dependencies of the Hall coefficient R H and Seebeck coefficient S at room temperature on the thickness ( d=10–550 nm) of thin PbTe films prepared by the thermal evaporation in vacuum of n-type PbTe crystals with various charge carrier concentrations (10 17–10 19 cm −3) and their deposition on mica substrates were obtained. It was established that, with decreasing thickness of PbTe films, a transition from an electron to a hole conductivity occurs, and the inversion point shifts to smaller d values as the electron concentration in the target material increases. The experimental R H( d) and S( d) dependencies are interpreted in terms of the acceptor states created by oxygen on the film surface. These dependencies were also calculated theoretically, taking into account the existence of two types of charge carriers (electrons and holes). The theoretical curves are found to be in good agreement with the experimental data.