Formation of indium-tin-oxide films by dip coating process using indium dipropionate monohydroxide

Indium-tin-oxide (ITO) transparent conducting films were successfully prepared by dip coating using a novel precursory material, indium dipropionate monohydroxide, In(OH)(C2H2COO)(2), which was synthesized by refluxing propionic acid (C2H5COOH) with indium oxide (In2O3) powders for 12 h. The coating solution consisted of indium dipropionate monohydroxide and tin tetrachloride, SnCl4.5H(2)O, dissolved in propionic acid (concentration of total metal ions, 0.1 mol/l; Sn/(In+Sn), 0.1, 3, 5, 10 and 15 at.%). The dip coating (withdrawal rate: 10 cm/min) and the heating on a hot plate (similar to400degreesC, 5 min) were repeated 40 times to fabricate similar to200-nm-thick ITO films. The resistivity of the as-deposited films remarkably decreased by increasing the film thickness to similar to200 nm; similar to1.9 X 10(-3) ohm cm was achieved for the ITO films with 5 at.% Sn. Annealing at 600 degreesC for 1 h in a N-2-0.1% H-2 atmosphere further lowered the resistivity The minimum value at the present (3.1 X 10(-4) ohm cm) was compatible with the reported minimums for the previous dip-coated films. The influence of the tin concentration and film thickness on the carrier electron concentration and the mobility was discussed and compared with other dip-coated ITO films. (C) 2002 Elsevier Science B.V All rights reserved.