Investigation of structural, electrical and optical properties of CU1-XAGXINSE2 thin films as a function of X content

Güllü, Hasan Hüseyin
In this work, we will focus on the quaternary system Cu1-xAgxInSe2 (CAIS) to investigate the effects of silver (Ag) contribution and exchange with copper (Cu) in CuInSe2. This system is located between the ternary semiconducting chalcopyrite compounds CuInSe2 and AgInSe2. These are two most popular materials applied in photovoltaic cells because of their high optical absorption coefficient, which is an important factor for the manufacture of devices, direct energy gap with values Eg ~1.05 and 1.24 eV, respectively, and excellent thermal stabilities in air. As being a quaternary alloy, we expect that Cu1-xAgxInSe2 will show the advantage of a large degree of variation of their properties as a function of the composition, which allows adjusting of the band gap and other properties. We will analyze the behavior of Ag in the structure depending on the annealing and the effects of the Ag exchange to the Cu vacancies in this crystal structure by changing x (Ag content). The crystals will be characterized structurally by X-ray diffraction (XRD). It will be used to prove crystallinity, determine perfection and lattice parameters depending on composition. Surface morphology and stoichiometry will be examined using scanning electron microscope (SEM) equipped with EDXA. Moreover, electrical properties including the temperature dependent electrical conductivity, and carrier concentrations and mobility extracted from Hall effect measurements, and, optical properties including absorption coefficient, photoconductivity, spectral transmission, and optical band gap have been determined to characterize Cu1-xAgxInSe2 thin films deposited using e-beam evaporation technique.


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Citation Formats
H. H. Güllü, “Investigation of structural, electrical and optical properties of CU1-XAGXINSE2 thin films as a function of X content,” M.S. - Master of Science, Middle East Technical University, 2010.