The properties of antimony-doped tin oxide thin films from the sol-gel process

Antimony-doped tin oxide thin films have a range of technical applications as conductive coatings, and sol-gel processing seems to offer a number of advantages over other coating techniques. In this study, the sol was prepared from stannic chloride and antimony chloride in alcohol. Films were achieved either from spin-coating of colloidal gel suspensions or from spray-coating of suspensions of sol-gel-derived powder. Both coating methods result in thin films with similar visible light transmission (transmission >80%) and sheet resistance (similar to 5 x 10(7) Omega/square). However, the surface of the spin-coated films is much more smooth than that of spray-coated films, whilst the spray-coated films contain large particulates, which came from agglomerates in the powder suspensions. Antimony doping of the tin oxide produces a number of effects: it accelerates the gelation, reduces the particle size and the degree of crystallinity of the gel, and decreases the resistance of the powder and films. However, increase of antimony doping from 2.6 to 5.2 mol% does not further decrease the resistance.