%0 Journal Article
%T Characterization of Silver Oxide Films Formed by Reactive RF Sputtering at Different Substrate Temperatures
%A P. Narayana Reddy
%A M. Hari Prasad Reddy
%A J. F. Pierson
%A S. Uthanna
%J ISRN Optics
%D 2014
%R 10.1155/2014/684317
%X Silver oxide (A2O) films were deposited on glass and silicon substrates held at temperatures in the range 303¨C473£¿K by reactive RF magnetron sputtering of silver target. The films formed at room temperature were single phase Ag2O with polycrystalline in nature, while those deposited at 373£¿K were improved in the crystallinity. The films deposited at 423£¿K were mixed phase of Ag2O and Ag. Atomic force micrographs of the films formed at room temperature were of spherical shape grains with size of 85£¿nm, whereas those deposited at 473£¿K were with enhanced grain size of 215£¿nm with pyramidal shape. Electrical resistivity of the single phase films formed at room temperature was 5.2 ¡Á 10£¿3£¿¦¸cm and that of mixed phase was 4.2 ¡Á 10£¿4£¿¦¸cm. Optical band gap of single phase films increased from 2.05 to 2.13£¿eV with the increase of substrate temperature from 303 to 373£¿K, while in mixed phase films it was 1.92£¿eV. 1. Introduction Silver-oxygen system (Ag-O) was extensively attracted by researchers due to its novel applications in high density optical storage devices, gas sensors, photovoltaic cells, photo diodes, and antibacterial coatings [1¨C6]. This system exists in different defined compounds, namely, Ag2O, AgO, Ag3O4, Ag4O3, Ag2O3, and Ag4O4. Among these oxides, Ag2O is the most thermodynamically stable. The compound Ag2O possesses a simple cubic structure at room temperature [7]. Ag2O in thin film form is a p-type semiconductor with a band gap ranging from 1.2 to 3.4£¿eV due to the deviation in the stoichiometry, structure and crystallinity, phases, and physical properties arising from the employed deposition technique [8]. Thermal decomposition of silver oxide into oxygen and silver is the unique characteristics which led to the promising technological applications. Kim et al. [9] reported that silver oxide films also act as a mask layer in magneto-optical disk to enhance the magneto-optical signal. However, the high threshold of thermal decomposition temperature >673£¿K for silver oxide films has been a bottleneck of application in optical and magneto-optical storage [10, 11]. The Ag2O films grown with (111) orientation by rapid thermal annealing process at temperature of 473£¿K find application as readout layer in a magneto-optical disk. Peyser et al. [12] achieved strong photoactivated emission of nanoscale Ag2O for excitation with a wavelength <520£¿nm find application in blue optical lasers. Nanoparticles of Ag2O embedded in ZnO inhibit the degradation in the performance of photodetector when annealed in oxygen ambient at temperature of 473£¿K [3]. B¨¹chel et
%U http://www.hindawi.com/journals/isrn.optics/2014/684317/