PREPARATION AND CHARACTERIZATION OF SNO2 THIN-FILMS DEPOSITED BY SPRAY-PYROLYSIS FROM SNCL2 AND SNCL4 PRECURSORS

Highly transparent and conducting SnO2 thin films have been deposited by spray pyrolysis using SnCl2 and SnCl4 as precursor solutions and NH 4F and HF as sources of the doping impurities. The role of various dep osition parameters has been studied in detail and the optimum preparat ion conditions were obtained. A comparative study showed that the samp les prepared using SnCl2 as the precursor solution and HF as the sourc e of the doping impurities, present lower values of resistivity than t hose obtained from a precursor solution of SnCl4 and NH4F as doping so lution. SnO2 films with resistivities of about 2.5 x 10(-4) omega cm a nd transmittance greater than 90% were obtained in this work. X-ray di ffraction measurements indicated that the SnO2 films, prepared from Sn Cl4, present a preferential growth along the (200) direction whereas t he samples prepared from SnCl2 present a tendency to growth preferenti ally along the (101), (211) and (301) directions.