Structural, optical and electrical properties of copper (Cu) and [nickel (Ni), copper]: co‑doped SnO2 nanoparticles prepared by sol–gel method

Abstract

In this work, the un-doped, Cu-doped, and (Ni, Cu) co-doped SnO2 nanoparticles (NPs) were synthesized using the sol–gel method with a fxed concentration of copper dopant while varying the nickel concentrations. The structural, optical and electrical properties, as well as the surface morphology, were investigated systematically by various characterization tech niques. The X-ray difraction (XRD) study confrmed that the prepared samples had a tetragonal rutile crystal structure for all single-doped/co-doped and un-doped SnO2 NPs. The XRD results further confrmed that the crystalline sizes varied from 16 to 10 nm with the concentrations of the dopants. The UV–Vis difusion refectance spectroscopy (DRS) analysis showed that the optical band gap was found to be decreased from 3.38 to 3.27 eV when the dopant concentrations were increased. The energy dispersive analysis of X-ray spectra (EDX) results confrmed the presence of the expected elements in the pre pared samples. Three major photoluminescence (PL) emission peaks were observed in the visible region, with a small shift toward lower wavelengths with dopant and co-dopant concentrations. Chemical bonding and the position of the O–Sn–O bond at 600–660 cm−1 were confrmed by the Fourier transform infrared spectroscopy (FTIR) study. The activation energies and conduction mechanisms of the prepared samples were investigated using the Hall Efect measurement method. The I–V studies confrmed that the prepared samples had a good ohmic contact behavior and the resistivity decreased signifcantly for co-doped sample.