Synthesis of Zn2SnO4 particles and the influence of annealing temperature on the structural and optical properties of Zn2SnO4 films deposited by spraying nanoinks

Abstract

This work presents the results of the study of structural, substructural and optical properties of Zn2SnO4 nanoparticles (NPs) and films. NPs synthesized by the hydrothermal method during 28 h were chosen to form a nanoink from which films were obtained by spraying the solution it on glass substrates. Obtained Zn2SnO4 films were annealed in Argon atmosphere at Ta = (250–500) °C for 30 min and 60 min to remove organic impurities and optimize the film's physical properties. Since the choice of mineralizer determines a number of important characteristics of nanoparticles, a comprehensive study of the obtained samples grown using KOH as a mineralizer was conducted. The samples were characterized by X-ray diffraction analysis, Energy Dispersive X-ray (EDX) analysis, high-resolution transmission (HRTEM) and scanning electron (SEM) microscopy, Raman and optical spectroscopy. Analysis of morphology showed that synthesized films have a [220] growth texture with inverse spinel structure and consist of NPs, the size of which increases with the annealing temperature (Ta). It was identified that the size of the coherent scattering domain (CSD) in the sample increases with increasing Ta, while the level of microdeformations decreases. Raman spectra showed F2g(2), F2g(3) and A1g modes corresponding to the structure of inverse spinel Zn2SnO4. It is found, that the optical bandgap Eg of NPs decreases from 4.02 eV to 3.85 eV with an increase in growth time. On another hand, the optical bandgap Eg of films decreases with an increase in annealing temperature, Ta, from 4.04 eV to 3.63 eV.