Structure, optical and electrical properties of sol-gel derived Zn1.5+xSn1.5-xO4 nanostructured films for optoelectronic applications

This work reports the structure-property relationship of sol gel synthesized Zn1.5+xSn1.5-xO4 films using acetylacetone as precursor solvent and stabilizer. These samples were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), Raman spectroscopy, optical spectroscopy and Hall measurements. XRD study reveals the preferentially grown along (311) with a change in its intensity for different compositions in Zn-Sn-O system. The surface morphology varies with composition has been observed in both SEM and AFM studies. The dominant Raman active modes were observed at 556 and 667 cm(-1) corresponding to F-2g, and A(1g) modes respectively of Zn2SnO4 system. The optical gap varies between 3.85 eV to 3.96 eV and defect related emission spectra dominate the luminescence characteristics for the present system. The minimum electrical resistivity 8.4 x 10(-3) Omega-cm and maximum figure of merit of 0.09 Omega(-1) has been found for Zn2.25Sn0.75O4 films. These results show their suitability for fabrication of transparent conductors and other sensing device applications.