Bueno, Paulo Roberto [UNESP]Santos, M. A. [UNESP]Ramirez, M. A. [UNESP]Tararam, R. [UNESP]Longo, Elson [UNESP]Varela, José Arana [UNESP]2014-05-202014-05-202008-07-01Physica Status Solidi A-applications and Materials Science. Weinheim: Wiley-v C H Verlag Gmbh, v. 205, n. 7, p. 1694-1698, 2008.1862-6300http://hdl.handle.net/11449/25609The relationship between grain-boundary capacitance and extrinsic shallow donors caused by Nb addition to SnO2 center dot COO binary polycrystalline system has been investigated by means of combined techniques such as I-V characteristic response, complex impedance and capacitance analysis and electrostatic force microscopy. The estimated role of the Nb doping is to increase the concentration of shallow donors that are capable of enhancing the electronic donation to grain-boundary acceptors. This effect leads to the formation of potential barriers at grain boundaries with a simultaneous increase of grain-boundary capacitance and non-Ohmic features of the polycrystalline device doped with Nb atoms.1694-1698engArtigo10.1002/pssa.200723355WOS:000257828100031Acesso restrito04770459067332540000-0003-2827-0208