Chalcogenide Letters Vol. 10, No. 10, October 2013, p. 421 - 425 CHARACTERIZATION OF CdS THIN FILMS DEPOSITED BY CHEMICAL BATH DEPOSITION USING NOVEL COMPLEXING AGENTS A..CARRILLO-CASTILLO * , R. C. AMBROSIO LÁZARO a , E.M. LIRA OJEDA a , C. A. MARTÍNEZ PÉREZ a , M. A. QUEVEDO-LÓPEZ b F. S. AGUIRRE-TOSTADO C . a Instituto de Ingeniería y Tecnología, Universidad Autónoma de Ciudad Juárez. Ave. Del Charro 450 N, Cd. Juárez Chih. CP 32310, México. b Universidad de Sonora. Hermosillo, Sonora, C.P. 83000, México c Centro de Investigación en Materiales Avanzados, S. C. Unidad Monterrey, Alianza Norte 202, Parque de Investigación e Innovación Tecnológica, Apodaca, Nuevo León, C.P. 6628, México. Cadmium sulfide (CdS) thin films have been deposited by chemical bath deposition (CBD) at 70°C on glass substrates. In order to have a better control of deposition rate in CdS synthesis, Sodium borohydride and hydrazine were demonstrated as novel complexing agents. The structural, optical and electrical characteristics of the CdS thin films obtained were analyzed. Sodium borohydride as complex agent increased the deposition rate while hydrazine reduced the deposition rate due to higher complexation and slow generation of Cd 2+ while improving the morphology of CdS films. Homogeneous CdS thin films with hexagonal crystalline structure and energy band gap of 2.4 eV were obtained. The deposited thin films showed a good electrical conductivity with resistivity values in the order of 10-300 Ω-cm, suggesting a low metal-semiconductor contact resistivity as well. (Received August 26, 2013; Accepted October 31, 2013) Keywords: Chemical bath deposition; Cadmium sulphide; Complexing agent 1. Introduction II–VI compound semiconductor deposition from aqueous solution has gained attention due to the economical advantages and capability of large-area deposition [1-2]. Cadmium sulphide (CdS) is the most studied chalcogenide with a bandgap of 2.4 eV (in bulk) [3], additionally it was studied as the semiconductor active layer during the early development of Thin Film Transistors (TFTs) [4]. The application of CdS films as window layers in high efficiency solar cells based on cadmium telluride (CdTe) and copper indium gallium selenide Cu(In,Ga)Se 2 (CIGS) has recently increased the interest and studies on this material [5]. CdS thin films have been prepared by different methods (physical and chemical) such as electrostatic deposition [6], gas evaporation [7], micelles [8], chemical bath deposition (CBD) [9] etc. Among those, CBD process is attractive due to the simplicity and low cost, the technique can yield homogeneous, adherent, transparent, and highly stoichiometric CdS thin films [10,11]. In particular chemical bath deposition is a technique used to obtain thin inorganic semiconductor films from most cations of transition metals and metalloids, with anions of group VI, and more often, with sulphide and selenide ions. This technique is also known as solution growth, controlled precipitation, or simply a chemical deposition. CBD can be used to deposit any compound that satisfies four basic requirements: the material must be prepared by simple precipitation, the compound is highly insoluble in the solution, the compound is chemically stable in the solution * Corresponding autor: amanda.carrillo@uacj.mx