Photo‐Electrical Characterization of Silicon Micropillar Arrays with Radial p/n Junctions Containing Passivation and Anti‐Reflection Coatings |
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| Authors: | Wouter Vijselaar Rick Elbersen Roald M. Tiggelaar Han Gardeniers Jurriaan Huskens |
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| Affiliation: | 1. Molecular NanoFabrication, MESA+ Institute for Nanotechnology, University of Twente, Enschede, The Netherlands;2. Mesoscale Chemical Systems, MESA+ Institute for Nanotechnology, University of Twente, Enschede, The Netherlands;3. NanoLab Cleanroom, MESA+ Institute for Nanotechnology, University of Twente, Enschede, The Netherlands |
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| Abstract: | In order to assess the contributions of anti‐reflective and passivation effects in microstructured silicon‐based solar light harvesting devices, thin layers of aluminum oxide (Al2O3), silicon dioxide (SiO2), silicon‐rich silicon nitride (SiNx), and indium tin oxide (ITO), with a thickness ranging from 45 to 155 nm, are deposited onto regularly packed arrays of silicon micropillars with radial p/n junctions. Atomic layer deposition of Al2O3 yields the best conformal coating over the micropillars. The fact that layers made by low‐pressure chemical vapor deposition (SiO2 and SiNx) are not conformally deposited on the sidewalls of the Si micropillars do not influence the photoelectrical efficiency. For ITO, a change in composition along the micropillar height is measured, which leads to poor performance. For Al2O3, deconvolution of the contributions of passivation and anti‐reflection to the overall efficiency gain exhibits the importance of passivation in micro/nano‐structured Si devices. Al2O3‐coated samples perform the best, for both n/p and p/n configured pillars, yielding (relative) increases of 116% and 37% in efficiency of coated versus non‐coated samples for p‐type and n‐type base micropillar arrays, respectively. |
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| Keywords: | anti‐reflection coatings passivation radial p/n junction silicon micropillars solar cells |
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