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Preparation of Cadmium-free Buffer Layers for CIGS Solar Cells

CIGS 태양전지용 Cd-Free 버퍼층 제조

  • Moon, Jee Hyun (Department of Chemical & Biological Engineering, Gachon University) ;
  • Kim, Ji Hyeon (Department of Chemical & Biological Engineering, Gachon University) ;
  • Yoo, In Sang (Department of Chemical & Biological Engineering, Gachon University) ;
  • Park, Sang Joon (Department of Chemical & Biological Engineering, Gachon University)
  • 문지현 (가천대학교 화공생명공학과) ;
  • 김지현 (가천대학교 화공생명공학과) ;
  • 유인상 (가천대학교 화공생명공학과) ;
  • 박상준 (가천대학교 화공생명공학과)
  • Received : 2014.08.04
  • Accepted : 2014.10.14
  • Published : 2014.12.10

Abstract

Indium hydroxy sulfide ($In(OH)_xS_y$) as a cadmium (Cd)-free buffer layer for $CuInGaSe_2$ (CIGS) solar cells was prepared by the chemical bath deposition (CBD) and the reaction time was optimized. The band gap energy and transmittance data alongside the thickness results from the direct observation with focused ion beam system (FIB) could be a powerful tool for optimizing the conditions. In addition, X-ray diffractometer (XRD), X-ray photoelectron microscopy (XPS), and scanning electron microscope (SEM) were also employed for the layer characterization. The results indicated that the optimum reaction time for $In(OH)_xS_y$ buffer layer deposition by CBD was 20 min at $70^{\circ}C$ under the conditions employed. At the optimum conditions, the buffer layer thickness was near 57 nm and the band gap energy was 2.7 eV. In addition, it was found that there was no XPS peak shift in between the buffer layers deposited on molybdenum (Mo)/glass and that on CIGS layer.

Keywords

chemical bath deposition;Cd-free buffer layer;CIGS solar cells;$In(OH)_xS_y$;layer thickness

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