Surface and Coatings Technology 182 (2004) 156–160 0257-8972/04/$ - see front matter  2003 Elsevier B.V. All rights reserved. doi:10.1016/j.surfcoat.2003.07.004 Electrodeposition of CuInTe film from an acidic solution 2 T. Ishizaki *, N. Saito , A. Fuwa a, b a Department of Material Science and Engineering, School of Science and Engineering, Waseda University, Tokyo 169-8555, Japan a Department of Materials Processing Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8603, b Japan Received 6 February 2003; accepted in revised form 31 July 2003 Abstract Copper–indium–telluride films were electrochemically deposited from solutions containing CuCl , InCl , TeO and HCl. 2 3 2 Although a flat and smooth film with closely stoichiometric composition was deposited at y660 mV vs. AgyAgCl at 303 K from a solution of 2.5=10 mol dm CuCl , 1.0=10 mol dm InCl , 5.0=10 mol dm TeO and 0.1 mol dm HCl, y4 y3 y2 y3 y4 y3 y3 2 3 2 a polycrystalline CuInTe film was not obtained. Increasing the temperature from 303 to 363 K allowed the deposition at lower 2 overpotential of a polycrystalline CuInTe film with closely stoichiometric composition and increased indium content. The band 2 gap of the polycrystalline CuInTe film electrodeposited at 363 K at y660 mV was 0.98 eV. 2  2003 Elsevier B.V. All rights reserved. Keywords: Electrochemistry; Deposition process; Copper–indium–telluride 1. Introduction The ternary compound semiconductor copper–indi- um–telluride (CIT) has found application in optical and photovoltaic devices w1x. CIT is a direct band gap semiconductor with a reported band gap varying between 0.92 and 1.04 eV w2x. This band gap is very close to the optimal value for solar energy conversion. CIT shows great promise for solar cell applications because it can be prepared as both p- and n-types w3x. However, copper–indium–telluride has rarely been the subject of research and has been prepared in the past through dry processes such as the Bridgeman technique w4x and the thermal vacuum evaporation method w5x. The electrodeposition of semiconductor compounds offers several advantages over other physical and chem- ical deposition processes. It is both relatively easy and economical and is suitable for fabricating large area devices with controlled film thickness. Synthesis via dry processes requires high growth temperature, while elec- trodeposition can be conducted at lower temperatures. Despite these advantages, the electrodeposition of ter- *Corresponding author. Tel.yfax: q81-3-5286-3313. E-mail address: isizaki@moegi.waseda.jp (T. Ishizaki). nary copper–indium–telluride has been reported only by Bhattacharaya w6x and Lokhande w7x. Previously, we successfully electrodeposited Cu Te 2 film under diffusion-limited conditions w8x. At that time, it shows that CuInTe might be formed by electrodepos- 2 iting Cu Te with the incorporation (induced-codeposi- 2 tion) andyor UPD (underpotential deposition) of In, as has been demonstrated in the formation of CuInSe w9x. 2 Thus, in the present research, we attempted to prepare stoichiometric CuInTe via electrodeposition based on 2 our earlier results obtained in Cu Te preparation. In this 2 study, we have investigated the behavior of copper– indium–telluride electrodeposition in an acidic bath. We demonstrate here the composition control of electrode- posited CuInTe by varying both the cathode potential 2 applied and the concentration of the elements in the electrolyte. The effect of increasing the bath temperature on composition and crystallization was also investigated. 2. Experimental Acidic aqueous electrolytes containing CuCl , InCl , 2 3 TeO and HCl were employed for the electrodeposition 2 of CuInTe . All chemicals were of reagent grade and 2 were used without pretreatment. The specific resistance