Quantification of nanoscale density fluctuations in hydrogenated amorphous silicon
| Autor: | Gericke, Eike, Melskens, Jimmy, Wendt, Robert, Wollgarten, Markus, Hoell, Armin, Lips, Klaus |
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| Rok vydání: | 2020 |
| Předmět: | |
| Zdroj: | Phys. Rev. Lett. 125, 185501 (2020) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevLett.125.185501 |
| Popis: | The nanostructure of hydrogenated amorphous silicon (a Si:H) is studied by a combination of small-angle X-ray (SAXS) and neutron scattering (SANS) with a spatial resolution of 0.8 nm. The a-Si:H materials were deposited using a range of widely varied conditions and are representative for this class of materials. We identify two different phases which are embedded in the a-Si:H matrix and quantified both according to their scattering cross-sections. First, 1.2 nm sized voids (multivacancies with more than 10 missing atoms) which form a superlattice with 1.6 nm void-to-void distance are detected. The voids are found in concentrations as high as 6*10^19 ccm in a-Si:H material that is deposited at a high rate. Second, dense ordered domains (DOD) that are depleted of hydrogen with 1 nm average diameter are found. The DOD tend to form 10-15 nm sized aggregates and are largely found in all a-Si:H materials considered here. These quantitative findings make it possible to understand the complex correlation between structure and electronic properties of a-Si:H and directly link them to the light-induced formation of defects. Finally, a structural model is derived, which verifies theoretical predictions about the nanostructure of a-Si:H. Comment: Letter presenting a model for a-Si:H derived by SAXS and SANS |
| Databáze: | arXiv |
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