Structural, linear and nonlinear optical characterization of Ni and Al Co-Doped CdO semiconductor nanostructures for nonlinear optical device applications

Abstract

The effects of metallic doping (Ni and Al) on thin film CdO nanostructures have been investigated and their morphological, structural, linear and nonlinear optical properties have been studied. Thin films were grown using spray pyrolysis method with a substrate temperature of 300 °C for different Ni and Al doping concentrations (0, 1, 3, 5 and 10 wt%). Studies of films with Powder X-ray diffraction confirm the polycrystalline nature with the cubic crystal structure. The Scherer rule was employed to determine the crystallite size and found to be enhanced. The elemental analysis confirms the incorporation of Ni and Al into the host CdO matrix. The surface morphology was analysed using the Field Emission Scanning Electron Microscope and the grain size was found to be altered by increasing the doping content. To understand the characteristics of the defect state, open and closed aperture Z-scan measurement was performed using the DPSS continuous wave (532 nm) laser excitation and nonlinear absorption, refractive index and nonlinear susceptibility values of third order were calculated and found to be increasing with the increased concentration of the dopants. The encouraging findings of the nonlinear optical parameters with the increasing concentration of Ni and Al on CdO nanostructures indicate that doped films are a promising source for nonlinear device applications.