International Journal of Photoenergy · 2015 · 10 citations · 25 references
EngineeringMaterials EngineeringMaterials ScienceElectronic MaterialsSemiconductor MaterialsThin FilmsSemiconductor Crystal GrowthSemiconductor Thin FilmsSilicon MaterialsSolar Cell MaterialsSolar CellsThin-film MaterialsCrystal Orientation EffectsCrystal Preferred OrientationLight-absorbing LayersPolycrystalline SiliconSeed LayersSilicon Thin FilmsSubstrate EffectsThin-film Solar Cells
Producing large-grained polycrystalline Si (poly-Si) film on glass substrates coated with conducting layers is essential for fabricating Si thin-film solar cells with high efficiency and low cost. We investigated how the choice of conducting underlayer affected the poly-Si layer formed on it by low-temperature (500°C) Al-induced crystallization (AIC). The crystal orientation of the resulting poly-Si layer strongly depended on the underlayer material: (100) was preferred for Al-doped-ZnO (AZO) and indium-tin-oxide (ITO); (111) was preferred for TiN. This result suggests Si heterogeneously nucleated on the underlayer. The average grain size of the poly-Si layer reached nearly 20 µ m for the AZO and ITO samples and no less than 60 µ m for the TiN sample. Thus, properly electing the underlayer material is essential in AIC and allows large-grained Si films to be formed at low temperatures with a set crystal orientation. These highly oriented Si layers with large grains appear promising for use as seed layers for Si light-absorption layers as well as for advanced functional materials.
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Masashi Kurosawa, Naoyuki Kawabata, Taizoh Sadoh et al. · Applied Physics Letters · 2009 · 116 citations