PREPARATION AND STUDY OF DOPED AND UNDOPED TIN DIOXIDE FILMS BY THE OPEN-AIR CHEMICAL-VAPOR-DEPOSITION TECHNIQUE

Highly transparent and conducting undoped and doped (Mo, Sb, F) tin di oxide films have been prepared by the open air chemical vapour deposit ion technique. The electrical and optical properties have been studied in detail for films deposited on glass substrates. Surface morphology study by scanning electron microscope shows that for films deposited on glass substrates, Sb-and F-doped films have a larger grain size tha n undoped ones. Mo-doping, in contrast, produces smaller grains. Films deposited on mica and Al sheet substrate have also a larger grain siz e compared to those on glass substrate. Films of very high quality in terms of crystallinity, electrical conductivity and optical transmissi on were obtained when deposited at a substrate temperature of 400 degr ees C. The optimum concentration for each dopant, at which the sheet r esistance is a minimum, has been determined. 4.5 at.% F-doped SnO2, fi lms show the lowest resistivity, similar to 4 x 10(-4) Ohm cm, and an average optical transmission of 80% at a thickness of 3500 Angstrom. ( C) 1997 Elsevier Science S.A.