Fabrication, Characterization and Optical Studies of Cu(In1-xGax)3Se5 Bulk Compounds

Abstract

AbstractIn this paper we present the structural and optical properties of Cu(In1-xGax)3Se5 ternary and quaternary compounds crystals fabricated by horizontal Bridgman technique. The Cu(In1-xGax)3Se5 materials were characterized by Energy Dispersive Spectrometry (EDS), hot point probe method, X-ray diffraction, Photoluminescence (PL), and Optical response (Photoconductivity). The Cu(In1-xGax)3Se5 have an Ordered Vacancy Chalcopyrite-type structure with lattice constants varying as a function of the x composition. A good stœchiometry given by the EDS characterization method is well observed in our samples and its magnitude deviation Δy is slight; so, our samples present a nearly perfect stœchiometry (Δy = 0) [1]. X-Ray diffraction patterns show the presence of many preferential orientations according to the planes (112), (220) and (312) of all the samples [2]. Also, it shows a linear shifting of peaks towards the higher magnitudes of 2θ when the x composition increases. These compounds can be of stanite structure [3] or an Ordered Vacancy Chalcopyrite structure (OVC) [4] or Ordered Defect Chalcopyrite Structure (ODC). We observe a large shift of the main PL and optical response emission peak versus x composition. The band gap energy of Cu(In1-xGax)3Se5 compounds is found to vary from 1.23 eV to 1.85 eV as a function of x. [1] Migual A. Contreras, Holm Wiesner, Rick Mtson, John Tuttle, Kanna Ramanathan, Rommel Noufi, Mat. Res. Soc. Symp. Proc. Vol. 426 (1996) 243-254. [2] Ariswan, G. El Haj Moussa, M. Abdelali, F. Guastavino, C. Llinares, Solid State Communications 124 (2002) 391-396. [3] M. Suzuki, T. Uenoyama, T. Wada, T. Hanada, Y. Nakamura, Jpn. J. Appl. Phys. 36 L1139 (1997). [4] Kristjan Laes, Sergei Bereznev, A. Tverjanovich, E.N. Borisov, Tiit Varema, Olga Volobujeva , Andres Öpik. Thin Solid Films 517 (2009) 2286–2290.