Structural, optical, and electronic structure properties of Cu substituted NiO solid solutions
Abstract
A comprehensive investigation of the electronic structure, both occupied and unoccupied states, of phase-pure Ni1−xCuxO (x = 0, 0.06, 0.10, 0.15, 0.22, 0.25) solid solutions is presented through the analysis of x-ray absorption near edge structure (XANES) spectra along with valence band (VB) structure using off-resonant and resonant photoelectron spectroscopy (PES). Structural analysis using x-ray diffraction and extended x-ray absorption fine structure (EXAFS) confirm a linear variation in the lattice parameter and bond lengths with increasing Cu concentration. A minor change (∼0.2 eV) in the optical bandgap, even at 25% of Cu substitution, is attributed primarily to the localized Ni 3d states in the conduction band. Resonant PES identifies distinct Ni and Cu derived states in the VB, confirming the charge transfer insulating nature of the solid solution. XANES study confirms the presence of Ni and Cu ions in the 2+ oxidation state.
Article Details
Journal Info
Journal of Applied Physics
American Institute of Physics
Authors (10)
Kiran Baraik
Synchrotrons Utilization Section, Raja Ramanna Centre for Advanced Technology 2 , Indore 452013,
Velaga Srihari
High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Center 3 , Trombay, Mumbai 400085,
Rajashri R. Urkude
Beamline Development and Application Section, Bhabha Atomic Research Center 4 , Trombay, Mumbai 400085,
Pragya Tiwari
Accelerator Physics and Synchrotrons Utilization Division, Raja Ramanna Centre for Advanced Technology 1 , Indore 452013,
Mukul Gupta
R. J. Choudhary
UGC-DAE Consortium for Scientific Research 5 , Khandwa Road, Indore, Madhya Pradesh 452017,
Chandrachur Mukherjee
Homi Bhabha National Institute, Training School Complex 2 , Anushakti Nagar, Mumbai 400094,
Biplab Ghosh
Beamline Development and Application Section, Bhabha Atomic Research Center 4 , Trombay, Mumbai 400085,
Tapas Ganguli
Homi Bhabha National Institute, Training School Complex 2 , Anushakti Nagar, Mumbai 400094,
Shreyashkar Dev Singh
Accelerator Physics and Synchrotrons Utilization Division, Raja Ramanna Centre for Advanced Technology 1 , Indore 452013,