Effect of Cu/Zn Substitution in MgO Nanostructures for Tuning the Optical Bandgap and Structural Properties

Abstract

Low cost co-precipitation method was used to synthesize Cu (0–0.05) doped MgO samples with fixed concertation of Zn=0.01. X-ray diffraction (XRD) spectra confirmed the phase purity of the samples for 0⩽Cu⩽0.03 doping concentration. The secondary phase for 0.04⩽Cu⩽0.05 exhibited the formation of mixed metal oxides. The crystallite size was found to increase from 17.5 to 23.5 nm for 0⩽Cu⩽0.03 and then decreased from 22 to 18.5 nm for 0.04⩽Cu⩽0.05. The estimated bandgap first reduced from 5.48 to 4.88 eV and then increased from 5.21 to 5.36 eV. The morphology of the samples transformed from spheroidal shape to star-like shape. The obtained results reveal that the structural and optical property are in good agreement with the morphological transition. The peak shifting towards the lower values of vibrational frequency from 694 to 579 cm⁻¹ confirms the incorporation of Cu/Zn in Mg-O lattice. The tuning of optical bandgap and structural properties with varying dopant concentration in MgO nanomaterials can be used for multifunctional modern energy storage and optoelectronic devices.

Keywords

Cu/Zn doping / MgO / optical bandgap / morphology / vibrational modes