Sol-gel deposition and characterization of In6WO12 thin films

Indium tungsten oxide (In6WO12) powders and thin films were prepared from a 2,4-pentanedione solution containing In(NO3).xH(2)O and WCl6. X-ray diffraction results indicated that phase-pure In6WO12 powder formed after drying and heating the solution at 900 degreesC. Glancing X-ray diffraction results indicated that thin-film samples prepared on fused quartz substrates at 600 and 700 degreesC contained a disordered fluorite-related phase whereas those prepared at 800 degreesC contained the ordered compound-In6WO12. Films prepared at 900 degreesC reacted with the substrate to form In2Si2O7. Despite the chemical and structural similarity of In6WO12 to several indium-containing fluorite-related oxides, including In2O3, In3Sn4O12, and Ga3-xIn5+xSn2O16, the resistivity of the films prepared in this study ranged from 70 to 720 Ohm cm, which is several orders of magnitude higher than reported for the related oxides (approx. 10(-3) Ohm cm). The band gaps of the films prepared at 600 and 700 degreesC were estimated from optical transmittance measurements to be 4.1 and 3.8 eV, respectively. Films prepared at 700 degreesC exhibited substantial coloration when exposed to n-butyl lithium whereas those prepared at 800 degreesC did not. (C) 2002 Elsevier Science B.V. All rights reserved.