HIGHLY EFFICIENT OPTOELECTRONIC PROPERTIES OF DOUBLY DOPED SnO2 THIN FILM DEPOSITED BY SPIN COATING TECHNIQUE

Abstract

In this study, we investigated structural and optical properties of doubly doped SnO2 thin films prepared successfully by sol-gel spin coating technique on optical glass substrates. Low cost precursor SnCl2 .2H2O for host precursor and Sbcl3 and NH4F dopant source are used (for 4 % wt. Sb and 30 % wt. F). X-ray Diffractometer, UV-Vis spectrophotometer, scanning electron microscope (SEM) and atomic force microscopy (AFM) were performed on AFTO (Antimony and Fluorine Doped SnO2) films. Structural studies reveals the presence of orthorhombic structure with preferential orientation of (021) and (042). The dislocation density of the doubly doped film is smaller than densities mentioned in the literature for doubly doped SnO2. SEM and AFM studies reveal the surface of AFTO to be made of nanocrystalline particles. The transmittance of the films in the visible range is 85-97 %, the best transparent film for doubly doped tin oxide films in the literature. Eg values are quite wide, 4.45 eV and better linearity was obtained in the (αhν) 2 vs. (hν) plots for Eg values. The band gap attained for the doubly doped films in this study is higher than the values reported for doubly doped tin oxide films prepared from prophanol solution of SnCl2.2H2O precursor. Our experimental results indicated that AFTO thin films with high optical quality could be synthesized by sol-gel spin coating techniques.