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Article Citation - WoS: 28Citation - Scopus: 10Electrical Conductivity and Hall Mobility in P-Type Tlgase2 Crystals(Pergamon-elsevier Science Ltd, 2004) Qasrawi, AF; Qasrawı, Atef Fayez Hasan; Gasanly, NM; Qasrawı, Atef Fayez Hasan; Department of Electrical & Electronics Engineering; Department of Electrical & Electronics EngineeringSystematic dark electrical conductivity and Hall mobility measurements have been carried out in the temperature range of 200-350 K on p-type TlGaSe2 crystals. The analysis of the temperature-dependent electrical conductivity and carrier concentration reveals the extrinsic type of conduction with an acceptor impurity level located at 0.33 eV, and donor and acceptor concentrations of 9.0 x 10(15) and 1.3 x 10(16) cm(-3), respectively. A hole and electron effective masses of 0.520m(0) and 0.325m(0), respectively, with a donor to acceptor compensating ratio of 0.69 are also being identified. The Hall mobility is found to be limited by the hole-phonon short-range interactions scattering with a hole-phonon coupling constant of 0.17. (C) 2004 Elsevier Ltd. All rights reserved.Article Citation - WoS: 28Citation - Scopus: 29Annealing Effects on the Structural and Optical Properties of Agin5s8< Thin Films(Elsevier Science Sa, 2008) Qasrawi, A. F.; Qasrawı, Atef Fayez Hasan; Qasrawı, Atef Fayez Hasan; Department of Electrical & Electronics Engineering; Department of Electrical & Electronics EngineeringDue to its importance as a perspective material for application in optoelectronic semiconductor devices, the thermal annealing effects on the structural and optical properties of the as-grown vacuum evaporated AgIn5S8 thin films have been investigated. The X-ray data analysis have shown that these films are polycrystalline in nature and exhibit better crystallization with increasing crystallite size and slightly, decreasing unit cell lattice parameter as annealing temperature is raised from 450 to 600 K. The optical energy band gap for the as-grown and thermally annealed films is found to be of direct allowed transitions type. The energy band gap exhibited values of 1.78, 1.74 and 1.62 eV as the samples were annealed at, 450 and 600 K, respectively. This indicates the ability of altering the band gap values of this material by the thermal annealing process. The structural and optical features seem to be suitable for semiconductor device production such as solar cell converters, which has successfully been fabricated by others, metal-insulator-semiconductor (MIS) and metal - oxide - semiconductor (MOS) devices, as well. (c) 2007 Elsevier B.V. All rights reserved.
