Current–voltage characteristic behaviour of dense Zn2SnO4-ZnO ceramics

The present work deals with the electrical characterization of undoped Zn2SnO4 (ZTO) and SnO2-doped ZnO bulk ceramics in order to clarify the role played by the ZTO spinel type phase in the electrical response of these materials. For this purpose, SnO2-doped ZnO materials with SnO2 concentrations of 0.1, 1 and 10 mol% have been prepared by co-precipitation and undoped ZTO powders have been prepared by a classical mixing oxide procedure. ZTO materials with 90–92% of the theoretical density have been obtained and non-linear behaviour is observed for ZTO- and SnO2-doped ZnO materials. For SnO2-doped ZnO the appearance of non-linear I–V behaviour is mainly dominated by the formation of the ZTO phase and the interfaces associated to its presence. ZTO shows a NTC behaviour that is in disagreement with the PTC behaviour previously reported in the literature.