Electrochemically Assisted Deposition as a New Route to Transparent Conductive Indium Tin Oxide Films

Abstract

Tin-doped indium oxide (ITO) films with Sn/In atomic ratios in the range 0−0.1 were synthesized by electrochemically assisted deposition (EAD). The process involves a fast one-step cathodic deposition of a highly crystalline In−Sn hydroxide (InSnOH) film followed by thermal conversion into ITO at 300 °C. The cathodic precipitation of InSnOH is preceded by formation of an In−Sn complex in solution. The films were characterized by field emission scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, UV−visible spectroscopy, and electrical measurements. In the Sn/In atomic ratio range 0−0.1, InSnOH and ITO films adopt the morphologies and cubic crystal structures of In(OH)3 and In2O3, respectively. The atomic environment of Sn and O atoms in the ITO films was shown to resemble that of films deposited by other techniques and commercial ITO samples made by chemical vapor deposition. Separate tin oxide/hydroxide phases were not observed by any of the characterization methods. The mor...