Comparison of the top-down and bottom-up approach to fabricate nanowire-based silicon/germanium heterostructures
| Autor: | Seref Kalem, T.K. Nguyen-Duc, U. Gösele, Peter Werner, W. Erfurth, Manfred Reiche, P. Das Kanungo, Nadine Geyer, Horst Blumtritt, Nikolai Zakharov, A. Wolfsteller |
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| Rok vydání: | 2010 |
| Předmět: |
Materials science
Silicon Metals and Alloys Nanowire chemistry.chemical_element Germanium Nanotechnology Surfaces and Interfaces Isotropic etching Surfaces Coatings and Films Electronic Optical and Magnetic Materials chemistry Materials Chemistry Reactive-ion etching Vapor–liquid–solid method Electron-beam lithography Molecular beam epitaxy |
| Zdroj: | Thin Solid Films. 518:2555-2561 |
| ISSN: | 0040-6090 |
| DOI: | 10.1016/j.tsf.2009.08.021 |
| Popis: | Silicon nanowires (NWs) and vertical nanowire-based Si/Ge heterostructures are expected to be building blocks for future devices, e.g. field-effect transistors or thermoelectric elements. In principle two approaches can be applied to synthesise these NWs: the ‘bottom-up’ and the ‘top-down’ approach. The most common method for the former is the vapour–liquid–solid (VLS) mechanism which can also be applied to grow NWs by molecular beam epitaxy (MBE). Although MBE allows a precise growth control under highly reproducible conditions, the general nature of the growth process via a eutectic droplet prevents the synthesis of heterostructures with sharp interfaces and high Ge concentrations. We compare the VLS NW growth with two different top-down methods: The first is a combination of colloidal lithography and metal-assisted wet chemical etching, which is an inexpensive and fast method and results in large arrays of homogenous Si NWs with adjustable diameters down to 50 nm. The second top-down method combines the growth of Si/Ge superlattices by MBE with electron beam lithography and reactive ion etching. Again, large and homogeneous arrays of NWs were created, this time with a diameter of 40 nm and the Si/Ge superlattice inside. |
| Databáze: | OpenAIRE |
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