Catalytic Hydrogen Doping of NdNiO3 Thin Films under Electric Fields.

The electric-field-assisted hydrogenation and corresponding resistance modulation of NdNiO3 (NNO) thin-film resistors were systematically studied as a function of temperature and dc electric bias. Catalytic Pt electrodes serve as triple-phase boundaries for hydrogen incorporation into a perovskite lattice. A kinetic model describing the relationship between resistance modulation and proton diffusion was proposed by considering the effect of the electric field during hydrogenation. An electric field, in addition to thermal activation, is demonstrated to effectively control the proton distribution along its gradient with an efficiency of ∼22% at 2 × 105 V/m. The combination of an electric field and gas-phase annealing is shown to enable the elegant control of the diffusional doping of complex oxides.

Characteristics of the Mg-Doped Cr-Deficient CuCr0.95Mg0.02O2 Thin Films Prepared by Using Pulsed Laser Deposition.

2 at% Mg doped thin films of delafossite CuCrO2 and Cr-deficient CuCr0.97O2 were prepared by pulsed laser deposition. The films were grown on c-sapphire single crystal substrates at a range of substrate temperatures, and the effects of the processing parameters on thin film properties were examined. The crystallinity improved with increasing substrate temperature and Mg-doping. The substitution of Mg in the CuCrO2 and Cr-deficient CuCr0.97O2 thin films increased the electrical conductivity significantly with a slight decrease in optical transmittance. By introducing Mg-doping to Cr-deficient CuCr0.97O2 thin films, a CuCr0.95Mg0.02O2 thin film with an electrical conductivity of 29.63 S/cm and a mean optical transmittance of 60% was fabricated.