Preparation and characterization of fluorine doped SnO2 thin film by vacuum coating technique

Tin dioxide thin films are prepared by vacuum coating method using powders made by sol-gel method. The powder doped using different percentages of fluorine, and the electric and optic properties of thin films formed from these are studied. X-ray diffraction pattern studies confirm improvement of crystalline nature as the percentage of fluorine is increased from 0-10wt %. The crystalline size is increased from 6.64nm to 66 nm by adding 6 wt% of fluorine. Increasing doping percentage leads to decrease in UV absorption and increase in transmittance in the visible range, both of which can be attributed to the observed increase in crystallinity. The effect of fluorine on electrical conductivity, activation energy and band-gap is also studied and it is observed that the electrical properties of the film increases as the percentage of fluorine increases. However the amount of fluorine above a certain limit reduces the optical and electrical  properties.