Applied Physics Letters · 2006 · 93 citations · 15 references
Doped ZnoOptical MaterialsEngineeringChemistrySemiconductor NanostructuresSemiconductorsIi-vi SemiconductorOptical PropertiesZno Polycrystalline SamplesMaterials ScienceMaterials EngineeringElectrical EngineeringOxide ElectronicsIntrinsic ImpuritySemiconductor MaterialElectrical PropertySpecific ResistanceApplied PhysicsD-d Transition BandsUndoped ZnoOptoelectronicsElectrical Resistivity
We report on the transport and optical properties of Ni doped ZnO polycrystalline samples. Ni doping in ZnO could be achieved to a small concentration (2mol%). Diffuse reflectance spectroscopy of doped ZnO showed the existence of d-d transition bands at 430, 580, and 655nm which are characteristic of Ni (II) with tetrahedral symmetry. Resistivity was found to be activated. The value of activation energy of undoped ZnO was about 90meV. It was found to decrease to 60meV for Zn0.99Ni0.01O and to 10meV for Zn0.98Ni0.02O. The decrease in resistivity was found to be in accordance with the impurity d-band splitting model.
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