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Article Citation - WoS: 18Citation - Scopus: 18Heat Treatment Effects on the Structural and Electrical Properties of Thermally Deposited Agin5s8< Thin Films(Pergamon-elsevier Science Ltd, 2011) Qasrawi, A. F.; Kayed, T. S.; Ercan, FilizThe heat treatment effects on structural and electrical properties of thermally deposited AgIn5S8 thin films have been investigated. By increasing the annealing temperature of the sample from 450 to 500 K, we observed a change in the crystallization direction from (420) to (311). Further annealing of the AgIn5S8 films at 550, 600 and 650 K resulted in larger grain size in the (311) preferred direction. The room temperature electrical resistivity, Hall coefficient and Hall mobility were significantly influenced by higher annealing temperatures. Three impurity levels at 230, 150, and 78 meV were detected for samples annealed at 350 K. The electrical resistivity decreased by four orders of magnitude when the sample annealing temperature was raised from 350 to 450 K. The temperature dependent electrical resistivity and carrier concentration of the thin film samples were studied in the temperature ranges of 25-300 K and 140-300 K, respectively. A degenerate-nondegenerate semiconductor transition at approximately 180 was observed for samples annealed at 450 and 500 K. Similar type of transition was observed at 240 K for samples annealed at 600 and 650 K. (C) 2011 Elsevier Ltd. All rights reserved.Article Citation - WoS: 10Citation - Scopus: 10Light Intensity Effects on Electrical Properties of Agin5s8< Thin Films(Elsevier Science Sa, 2011) Qasrawi, A. F.The light illumination effects on the current conduction mechanism in thermally annealed polycrystalline AgIn5S8 thin films has been investigated by means of dark and photoexcited conductivity measurements as a function of temperature. The dark electrical conductivity analysis in the temperature region of 30-300 K, reflected the domination of thermionic emission and variable range hopping of charge carriers over the grain boundaries above and below 90 K, respectively. Conductivity activation energies of similar to 155 and 78 meV (in the temperature regions of 230-300 K and 90-220 K. respectively), a density of localized states (evaluated assuming a localization length of 5A(0)) of 1.17 x 10(20) cm(-3) eV(-1), an average hopping distance of 41.51 A(0) (at 60 K) and an average hopping energy of 28.64 meV have been determined from the dark electrical measurements. When the sample was exposed to illumination at specific excitation intensity, the values of the conductivity activation energy, the average hopping energy and the average hopping range were decreased significantly. On the other hand, the density of localized states near the Fermi level increased when the light intensity was increased. Such behavior is attributed to the temporary shift in Fermi level and/or trap density reduction by electron-hole recombination. (C) 2011 Elsevier B.V. All rights reserved.
