Effect of Na presence during CuInSe2 growth on stacking fault annihilation and electronic properties
While presence of Na is essential for the performance of high-efficiency Cu(In,Ga)Se2 thin film solar cells, the reasons why addition of Na by post-deposition treatment is superior to pre-deposition Na supply—particularly at low growth temperatures—are not yet fully understood. Here, we show by X-ra...
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Veröffentlicht in: | Applied physics letters 2015-10, Vol.107 (15) |
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Hauptverfasser: | , , , , , , , , , , , |
Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | While presence of Na is essential for the performance of high-efficiency Cu(In,Ga)Se2 thin film solar cells, the reasons why addition of Na by post-deposition treatment is superior to pre-deposition Na supply—particularly at low growth temperatures—are not yet fully understood. Here, we show by X-ray diffraction and electron microscopy that Na impedes annihilation of stacking faults during the Cu-poor/Cu-rich transition of low temperature 3-stage co-evaporation and prevents Cu homogeneity on a microscopic level. Lower charge carrier mobilities are found by optical pump terahertz probe spectroscopy for samples with remaining high stacking fault density, indicating a detrimental effect on electronic properties if Na is present during growth. |
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ISSN: | 0003-6951 1077-3118 |
DOI: | 10.1063/1.4933305 |