ISSN 1063-7826, Semiconductors, 2014, Vol. 48, No. 9, pp. 1242–1247. © Pleiades Publishing, Ltd., 2014. Original Russian Text © A.P. Dostanko, O.A. Ageev, D.A. Golosov, S.M. Zavadski, E.G. Zamburg, D.E. Vakulov, Z.E. Vakulov, 2014, published in Fizika i Tekhnika Poluprovodnikov, 2014, Vol. 48, No. 9, pp. 1274–1279. 1242 1. INTRODUCTION In recent years, renewed interest in thin-film zinc oxide (ZnO) layers has been noted. The increased interest in this field is caused by the unique combina- tion of optical and electrical properties of zinc oxide. Zinc-oxide films that possess a high degree of chemi- cal inertness and resistance to atmospheric effects are used as conductive coatings, transparent in the infra- red (IR) and visible spectral regions, for electrical con- tacts and buffer layers of thin-film solar cells and information display units [1, 2]. The doping of ZnO films makes it possible to attain a resistivity up to 2 × 10 –4 Ω cm [3, 4]. Zinc-oxide films possess good piezo- electric and electroluminescence characteristics and can be used as functional layers in devices, whose operation is based on surface acoustic waves [5, 6], sources and detectors of ultraviolet (UV) and IR radi- ation, optical shutters, and nonlinear optical elements [7–9]. The ability of heated ZnO films to adsorb cer- tain gases and, in this case, to change conductivity makes possible the use of these films as active elements of gas sensors [10]. The widespread industrial use of devices based on ZnO layers is limited by the complexity of the produc- tion of ZnO films with specified functional character- istics. Zinc oxide belongs to the group of direct-gap semiconductors, and the properties of the deposited films depend to a large extent on the concentration of free charge carriers controlled by oxygen vacancies [2]. The currently most widely applied method of the formation of thin-film ZnO layers is reactive magne- tron sputtering [11, 12]. This technique provides a means for varying the conditions of film deposition within wide limits and, thus, for controlling the elec- trical and structural properties of the deposited coat- ing. Among the disadvantages of this technique, the complexity of the production of stoichiometric layers without heating the substrates must be mentioned. The magnetron sputtering procedures developed thus far provide the production of ZnO layers at tempera- tures higher than 200°C, which restricts the field of possible applications of the layers [13]. For example, in the case of deposition onto polymeric substrates, the temperature during deposition of the films must be no higher than 80–120°C (the typical temperatures are 70–80°C). In addition, it is found that, in the case of the magnetron deposition of ZnO films, the distri- bution of the optical and electrical characteristics of the resulting ZnO layers is nonuniform because of bombardment of the growing film by high-energy neg- ative oxygen ions and atoms [14]. At the same time, inadequate attention is given to the use of the ion-beam sputtering of oxide targets. This technique provides deposition rates comparable to those in the above-mentioned technique [15] and the formation of stoichiometric layers without heating of the substrate. In addition, the technique allows comparatively easy scaling [16]. Thus, the purpose of this study is to explore the electrical and optical characteristics of ZnO films deposited by the ion-beam sputtering of a ZnO oxide target without heating of the substrate. Electrical and Optical Properties of Zinc-Oxide Films Deposited by the Ion-Beam Sputtering of an Oxide Target A. P. Dostanko a , O. A. Ageev b , D. A. Golosov a ^, S. M. Zavadski a , E. G. Zamburg b , D. E. Vakulov b , and Z. E. Vakulov b a Belarusian State University of Informatics and Radioelectronics, Minsk, 220013 Belarus ^e-mail: dmgolosov@gmail.com b Southern Federal University, Taganrog, 347928 Russia Submitted November 25, 2013; accepted for publication December 3, 2013 Abstract—The influence of the parameters of the deposition process on the stoichiometric composition and electrical and optical properties of ZnO films deposited by the ion-beam sputtering of a ZnO target is studied. It is established that, upon sputtering of a ZnO target with stoichiometric composition, there is a deficit of oxygen in the films deposited. Even for the case of target sputtering in a pure O 2 atmosphere, the stoichiom- etry index of the films is no higher than 0.98. A decrease in the oxygen content in the films is accompanied by a sharp decrease in the resistivity to 35–40 Ω m, narrowing of the optical band gap, and a shift of the optical transmittance edge from 389 to 404 nm. All of the variations in the optical and electrical properties of the ZnO films can be attributed to variations in the concentration and mobility of free charge carriers in the films. DOI: 10.1134/S1063782614090073 FABRICATION, TREATMENT, AND TESTING OF MATERIALS AND STRUCTURES