Effective passivation of silicon surfaces by ultrathin atomic-layer deposited niobium oxide
| Autor: | J. H. Deijkers, Wilhelmus J. H. Berghuis, Saravana Balaji Basuvalingam, B. W. H. van de Loo, Bart Macco, Lachlan E. Black, Jimmy Melskens, Wilhelmus M. M. Kessels, Martin Hermle, Martin Bivour |
|---|---|
| Přispěvatelé: | Plasma & Materials Processing, Applied Physics and Science Education, Selective atomic-scale processing for nanoelectronics, Atomic scale processing, Processing of low-dimensional nanomaterials, Publica |
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
010302 applied physics
Materials science Physics and Astronomy (miscellaneous) Passivation Silicon business.industry Herstellung und Analyse von hocheffizienten Solarzellen chemistry.chemical_element 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Silicium-Photovoltaik Atomic layer deposition chemistry Photovoltaik 0103 physical sciences Optoelectronics Niobium oxide Crystalline silicon Thin film 0210 nano-technology Forming gas business Silicon oxide |
| Zdroj: | Applied Physics Letters, 112(24):242105. American Institute of Physics |
| ISSN: | 0003-6951 |
| Popis: | This letter reports on effective surface passivation of n-type crystalline silicon by ultrathin niobium oxide (Nb2O5) films prepared by atomic layer deposition (ALD) and subjected to a forming gas anneal at 300 °C. A champion recombination parameter J0 of 20 fA/cm2 and a surface recombination velocity Seff of 4.8 cm/s have been achieved for ultrathin films of 1 nm. The surface pretreatment was found to have a strong impact on the passivation. Good passivation can be achieved on both HF-treated c-Si surfaces and c-Si surfaces with a wet-chemically grown interfacial silicon oxide layer. On HF-treated surfaces, a minimum film thickness of 3 nm is required to achieve a high level of surface passivation, whereas the use of a wet chemically-grown interfacial oxide enables excellent passivation even for Nb2O5 films of only 1 nm. This discrepancy in passivation between both surface types is attributed to differences in the formation and stoichiometry of interfacial silicon oxide, resulting in different levels of chemical passivation. On both surface types, the high level of passivation of ALD Nb2O5 is aided by field-effect passivation originating from a high fixed negative charge density of 1-2 × 1012 cm-3. Furthermore, it is demonstrated that the passivation level provided by 1 nm of Nb2O5 can be further enhanced through light-soaking. Finally, initial explorations show that a low contact resistivity can be obtained using Nb2O5-based contacts. Together, these properties make ALD Nb2O5 a highly interesting building block for high-efficiency c-Si solar cells. |
| Databáze: | OpenAIRE |
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