Strain relief: Mainspring of Ge semiconducting nanostructures growth on LaAlO3(001)
| Autor: | José Manuel, Miriam Herrera, Rafael García, D. Dentel, Jean-Luc Bischoff, Emmanuel Denys, Hussein Mortada, Francisco M. Morales, Mickael Derivaz |
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| Rok vydání: | 2012 |
| Předmět: |
Materials science
Polymers and Plastics Metals and Alloys Substrate (electronics) Surface energy Electronic Optical and Magnetic Materials chemistry.chemical_compound Crystallography Lattice constant Electron diffraction chemistry X-ray photoelectron spectroscopy Lanthanum aluminate Transmission electron microscopy Ceramics and Composites Molecular beam epitaxy |
| Zdroj: | Acta Materialia. 60:1929-1936 |
| ISSN: | 1359-6454 |
| Popis: | We report on the initial growth mechanisms of Ge on LaAlO3(0 0 1), a crystalline oxide with a high dielectric constant (high-κ material). Chemical and structural properties were investigated in situ, through X-ray photoelectron spectroscopy and reflection high-energy electron diffraction, and ex situ by using high-resolution transmission electron microscopy. Ge was deposited by molecular beam epitaxy at 600 °C on a c(2 × 2) reconstructed LaAlO3(0 0 1) surface. At this temperature, a Volmer–Weber growth mode is observed due to a lower LaAlO3(0 0 1) surface free energy. It is characterized by the immediate formation of crystalline nano-islands. The Ge islands are relaxed and present an abrupt interface with the substrate. Some of them exhibit a preferential relationship in their heteroepitaxy, where the Ge(0 0 1) planes are parallel to the LaAlO3(0 0 1) ones, but rotated by 45° in the [0 0 1] direction. An additional rotation of 6° with respect to the growth axis is also observed, which compensates partially for the strain produced by the high lattice parameter mismatch (∼5%) between the semiconductor and the oxide. |
| Databáze: | OpenAIRE |
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