An electrochemical technique to deposit thin films of PbTe Anup Mondal a, ⁎ , Nillohit Mukherjee a , Sanjib Kumar Bhar b , Dipali Banerjee c a Department of Chemistry, Bengal Engineering and Science University, Shibpur, Howrah-711103, India b Department of Chemistry, Vivekananda College, Thakurpukur, Kolkata-700063, India c Department of Physics, Bengal Engineering and Science University, Shibpur, Howrah-711103, India Received 8 June 2005; received in revised form 14 October 2005; accepted 6 March 2006 Available online 19 April 2006 Abstract PbTe thin films were deposited electrochemically on transparent conducting oxide coated (TCO) glass substrates from a solution of lead acetate and TeO 2 at low pH. A lead (Pb) strip was used as a sacrificing anode and the TCO glass acted as the cathode, which were short-circuited externally. Depositions were carried out at different temperatures of the bath to study the growth kinetics and grain growth. X-ray diffraction technique, scanning electron microscopy, infrared spectroscopy and resistivity measurements were carried out to characterize the deposited films. The films were polycrystalline in nature with a cubic phase. © 2006 Elsevier B.V. All rights reserved. Keywords: Electrochemical deposition; Lead telluride; Structural properties; Optical properties; X-ray diffraction 1. Introduction Lead chalcogenides (PbS, PbSe, and PbTe) have been studied intensively for more than 40 years due to their interesting physical properties. They are narrow band gap semiconductors and find application as infrared detectors, thermoelectric materials and lasers in the 3–30 μm [1]. The IR sensitivities of these materials are similar to that of Cd 1-x Hg x Te, but are easier to grow; more stable and homogeneity problems regarding the chemical composition are much less severe. Lead chalcogenide thin films have been deposited by various techniques, e.g., chemical bath deposition [2,3], chemical vapour deposition [4], electrodeposition [5], molecular beam epitaxy [6], atomic layer epitaxy [7], hot-wall epitaxy [8], vacuum evaporation [9], magnetron sputtering [10], to name a few. Out of these, electrodeposition is a simple and low cost thin film deposition method with several advantages [11]. PbS [12] and PbSe [13] thin films have also been prepared by electrodeposition. Electrodeposition can be carried out using substrates with different sizes and shapes. Reactions involved occur closer to the equilibrium and the deposition process can be controlled more easily than in many high temperature gas phase methods. In addition, toxic gaseous precursors do not have to be used unlike in chemical gas phase methods. The only disadvantage is that the substrate has to be conductive. In the present work, an electrochemical (galvanic) technique has been employed to deposit thin films of PbTe on transparent conducting oxide (TCO) coated glass substrates. This technique is simpler than the conventional electrodeposition process of using a potentiostat/galvanostat. A metallic Pb strip has been used as an oxidisable electrode (anode) in an electrolytic solution, where the TCO glass substrate acted as the cathode, the two being short-circuited externally. The potential differ- ence between the two electrodes leads to the deposition of PbTe on the TCO substrate, hence no external biasing was required. This method was earlier used to deposit CdTe [14], CdSe [15], CdS [16] and ZnTe doped with Cu [17] thin films, however, for PbTe, it has been used for the first time. 2. Experimental details To start with, the substrates were cleaned with detergent and then dipped into concentrated chromic acid solution for about 20 min and washed thoroughly with cold distilled water, to remove any adhering impurities. They were then boiled in methanol and after drying, were degreased in a vapour of trichloroethelene. Thin Solid Films 515 (2006) 1255 – 1259 www.elsevier.com/locate/tsf ⁎ Corresponding author. E-mail address: anupmondal2000@yahoo.co.in (A. Mondal). 0040-6090/$ - see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.tsf.2006.03.004