EFFECT OF Ga CONTENT ON THE PROPEERTIES

OF QUATERNARY CuFe1-xGaxS2 THIN FILMS

 

J.C. Bernède1*, L. Barkat2, A. Khelil2, N. Hamdadou2

1 Université de Nantes, Nantes Atlantique Universités, LAMP, EA 3825, Faculté des  Sciences et des Techniques, 

2 rue de la Houssinière, BP 92208, Nantes, F-44000 France

2 Université d’Oran Es-Sénia, LPCM2E, Oran , Algérie

* Corresponding author. E-mail: jean-christian.bernede@univ-nantes.fr

Received: 31 July 2008; revised version accepted: 18 July 2009

 

Abstract

     We investigate the preparation of CuFexGa1-XS2 thin films with different composition of Ga, using a two stage deposition process. These thin films have been grown by sulphuration of CuFeGa alloy precursor. Cu/Fe/Ga…/Cu thin layers have been sequentially deposited by vacuum evaporation on a substrate heated at a temperature Ts = 450 °C. The relative thickness of the layers deposited was calculated to achieve the desired atomic ratio. These precursors are sulphured in a vacuum chamber using an S source. At the end of the process, the film exhibit a (112) preferential orientation. The structure of the film is the expected chalcopyrite structure. However the films are single CuFexGa1-XS2 phase only when Ga at.% = 6. For higher value some large grains of CuFeS2 are randomly distributed in the CuFexGa1-XS2 film. The optical study shows that, when the Ga atomic concentration in the films varies from 0 to 6 %, it is possible to increase the band  gap value from 0.575 to 0.795 eV.

 

Keywords: Chalcopyrite; Thin films; Alloy; X-ray diffraction; Band gap; CuFeSe2; CuGaSe2.

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