Correlated oxides that exhibit metal–insulator phase transitions are emerging as potential candidates for switching devices. One such material is SmNiO3, which has a transition temperature above room temperature (∼400 K in bulk crystals). In this work, we study temperature- and bias-dependent conduction mechanisms in epitaxial and polycrystalline SmNiO3 thin films. In both cases, at low electric field we observe thermally assisted hopping conduction through defect states with activation energies of ∼170 meV and ∼270 meV, respectively. At high electric field the conduction transitions to a space-charge limited regime controlled by an exponential trap distribution. The power law exponents are ∼3 in epitaxial films and ∼8–14 in polycrystalline films. The trap decay parameter in epitaxial films does not have the expected 1/T temperature dependence, which may be a signature of bandgap narrowing at high temperature because of the insulator-to-metal transition. The larger activation energy and power law dependency in polycrystalline films are consistent with additional defect density from extraneous phases. In polycrystalline films, current-voltage data measured perpendicular to the film surface are rectifying because of asymmetry in electrode work functions with a ratio of 104 at ± 1 V. We find that whereas the space-charge limited conduction for positive bias is bulk limited, the negative bias conduction is injection limited.

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