Hindawi Publishing Corporation Advances in Materials Science and Engineering Volume 2013, Article ID 256413, 6 pages http://dx.doi.org/10.1155/2013/256413 Research Article Photoconductive Multiplexing by ZnO:Zr:F Thin Solid Films C. Torres-Torres, 1 L. Castañeda, 2 and R. Torres-Martínez 3 1 Secci´ on de Estudios de Posgrado e Investigaci´ on, ESIME ZAC, Instituto Polit´ ecnico Nacional, 07738 M´ exico, DF, Mexico 2 Escuela Superior de Ingenier´ ıa Mec´ anica y El´ ectrica Unidad Ticom´ an, Instituto Polit´ ecnico Nacional, 07340 M´ exico, DF, Mexico 3 Centro de Investigaci´ on en Ciencia Aplicada y Tecnolog´ ıa Avanzada Unidad Quer´ etaro, Instituto Polit´ ecnico Nacional, 76090 Santiago de Quer´ etaro, QRO, Mexico Correspondence should be addressed to C. Torres-Torres; crstorres@yahoo.com.mx Received 30 May 2013; Accepted 1 August 2013 Academic Editor: Charles Sorrell Copyright © 2013 C. Torres-Torres et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Within this work, the nonlinear optical properties and electrical efects exhibited by zinc oxide thin flms codoped with zirconium and fuorine are reported. Te development of a simple photoconductive multiplexor system is proposed. Te samples were prepared by the ultrasonic spraying technique (UST). Spectroscopic studies and a vectorial two-wave mixing method were carried out with a nanosecond Nd:YAG laser system at 532nm. Experimental results indicate that afer the zirconium and fuorine doping, a strong third-order optical nonlinearity can be developed in the ZnO flms. Te nonlinear optical response seems to be dominantly originated by a two-photon absorption closely related to a photoconductive phenomenon. 1. Introduction Tere has been a renewed interest in the improvement of new nonlinear optical (NLO) materials for developing novel applications in photonics and integrated optics. Te demand of low-cost and high-performance optoelectronic systems has given rise to a progress related to more efcient transparent conductive oxide (TCO) thin flms. Regarding the popular TCOs, last decade has seen zinc oxide [ZnO] to emerge as one of the most important materials for manufacturing trans- parent electrodes. Besides their high optical transparency, the ZnO thin flms are highly stable in the hydrogen-plasma environment commonly used for the fabrication of silicon based p-i-n structures [1]. ZnO thin solid flms have been deposited by a wide variety of techniques, and among those, the ultrasonic spray technique has been successfully employed for developing conductive and transparent ZnO thin flms [2]. Keeping in mind the high optical transparency as one of the basic requirements for optoelectronic applications, the incorpora- tion of distinct dopants has been carried out to reduce the resistivity of ZnO flms [3]. Despite being similar to all the ultrasonic deposition processing routes, the ultrasonic spray technique involves numerous parameters and conditions to control the resulting physical properties of the ZnO thin flms [4]. For electrode manufacturing, oriented ZnO flms doped with adequate impurities are required to present a low resist- ivity; in this respect, stable ZnO thin flms could be fabricated utilizing group-III elements as dopants [5], but frequently, an additional postdeposition annealing either in vacuum or under molecular hydrogen atmosphere has been performed to achieve a low resistivity [6]. Furthermore, incorporation of some other elements with higher valencies into the ZnO lattice has been contemplated as another chance in the quest for improving its optical and electrical characteristics [7]. It is worth noting to mention that it has been considered to establish the substitution of divalent Zn atoms from the lattice sites of ZnO by tetravalent zirconium [Zr] atoms to achieve changes in the optical and electrical features of ZnO:Zr flms [8]. On the other hand, anionic impurities like fuorine [F] also have been employed to reduce the resistivity with an additional enhancement of the nonlinear optical properties of the flms, through the substitution of oxygen atoms of their lattice [9, 10]. Since the inclusion of both anionic and cationic impu- rities helps to reduce the resistivity of some metal oxide