Diffusion Coefficients of Selenium and Gallium during the Cu(In_1-xGa_x)Se₂ Thin Films Preparation Process

Abstract:

Cu (In_1-xGa_x)Se₂ (CIGS) polycrystalline thin films with Ga-gradient structures were prepared by selenization of sputtered Cu-In-Ga precursors. The Ga contents of the as-selenized CIGS thin films were measured by EDS. With greater Ga content, the peaks in the diffraction pattern become broadened. Auger electron spectroscopy was used to measure the composition distribution of the Cu, In, Ga, and Se elements in the CIGS and CuInSe₂ films. At 300°C, the diffusion coefficients D_Se was approximately (6.7±1.0) x 10^-16 m²s^-1, and D_Ga was about (4.5±1.0) x 10^-18 m²s^-1. D_Se are two orders of magnitude greater than D_Ga, which is also the reason why the selected CIGS film was almost completely selenized, but still able to keep certain Ga-grading profile. The temperature used in this work is within the low temperature range of the two-step selenization approach, which is more suitable for low-cost substrates like flexible substrates.

• Periodical: Advanced Materials Research (Volume 815)
• Pages: 448-453
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.815.448
• Online since: October 2013
• Authors: Jian Wang, Ya Fei Zhang, Jie Zhu
• Keywords: Cu(In_1-xGa_x)Se₂, Diffusion Coefficient, Ga-Grading, Selenization

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