Nanoscale observation of surface potential and carrier transport in Cu2ZnSn(S,Se)4 thin films grown by sputtering-based two-step process |
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Authors: | Gee Yeong Kim Ju Ri Kim William Jo Dae-Ho Son Dae-Hwan Kim Jin-Kyu Kang |
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Affiliation: | 1.Department of Physics, Ewha Womans University, Seoul 120-750, Korea;2.Advanced Convergence Research Center, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 711-873, Korea |
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Abstract: | Stacked precursors of Cu-Zn-Sn-S were grown by radio frequency sputtering and annealed in a furnace with Se metals to form thin-film solar cell materials of Cu2ZnSn(S,Se)4 (CZTSSe). The samples have different absorber layer thickness of 1 to 2 μm and show conversion efficiencies up to 8.06%. Conductive atomic force microscopy and Kelvin probe force microscopy were used to explore the local electrical properties of the surface of CZTSSe thin films. The high-efficiency CZTSSe thin film exhibits significantly positive bending of surface potential around the grain boundaries. Dominant current paths along the grain boundaries are also observed. The surface electrical parameters of potential and current lead to potential solar cell applications using CZTSSe thin films, which may be an alternative choice of Cu(In,Ga)Se2.PACS number: 08.37.-d; 61.72.Mm; 71.35.-y |
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Keywords: | Cu2ZnSn(S Se)4 Cu(In Ga)Se2 Kesterite Conductive atomic force microscopy Kelvin probe force microscopy |
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