Zn-doped SnO2 nanostructures: structural, morphological and spectroscopic properties

Abstract

SnO2 is a promising material for optoelectronic, catalytic and sensing applications and is highly sensitive to the small amount of impurities that can change its properties drastically. In the present work, co-precipitation method was employed to synthesize pure and Zn-doped SnO2nanostructures. The effect of Zn doping (1, 3 and 5% molar ratio) on crystallographic and spectroscopic properties of SnO2 nanostructures has been studied. The X-ray diffraction results revealed that SnO2 possesses tetragonal rutile crystal structure with predominant (110) plane and the same structure was retained after doping with Zn. Raman shifts also confirmed the typical feature of the tetragonal rutile phase in all samples. Fourier transform infrared spectra revealed stretching mode of Sn–O bond and vibrational mode of O–Sn–O bond complementing the Raman spectroscopy results. Field emission scanning electron micrographs confirmed the variation in morphology of synthesized samples with Zn-dopant concentration. High-resolution transmission electron micrographs showed that the synthesized nanostructures were nearly spherical and average particle size varies between ~20–26 nm. UV–Visible results revealed that the band gap of the synthesized SnO2 nanoparticles increased with increase in Zn content. Photoluminescence spectroscopic results showed that emission intensity increased with increase in Zn content. The increased intensity of emission peaks may be ascribed to the development of defect states in the band gap of Zn-doped SnO2 nanoparticles.