Hole accumulation in Ge/Si core/shell nanowires (NWs) has been observed and quantified using off-axis electron holography and other electron microscopy techniques. The epitaxial [110]-oriented Ge/Si core/shell NWs were grown on Si (111) substrates by chemical vapor deposition through the vapor-liquid-solid growth mechanism. High-angle annular-dark-field scanning transmission electron microscopy images and off-axis electron holograms were obtained from specific NWs. The excess phase shifts measured by electron holography across the NWs indicated the presence of holes inside the Ge cores. Calculations based on a simplified coaxial cylindrical model gave hole densities of (0.4 ± 0.2) /nm(3) in the core regions.
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Nano Lett
June 2024
Quantum- and Nanoelectronics Lab, Department of Physics, University of Basel, 4056 Basel, Switzerland.
Gatemon qubits are the electrically tunable cousins of superconducting transmon qubits. In this work, we demonstrate the full coherent control of a gatemon qubit based on hole carriers in a Ge/Si core/shell nanowire, with the longest coherence times in group IV material gatemons to date. The key to these results is a high-quality Josephson junction obtained using a straightforward and reproducible annealing technique.
View Article and Find Full Text PDFJ Phys Chem C Nanomater Interfaces
January 2023
Department of Physics, University of Rome Tor Vergata, and INFN, Via della Ricerca Scientifica 1, I-00133 Rome, Italy.
The electronic properties of hydrogenated, spherical SiGe and GeSi core-shell nanocrystals, with a diameter ranging from 1.8 to 4.0 nm, are studied within density functional theory.
View Article and Find Full Text PDFMaterials (Basel)
September 2022
Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia.
We investigated the production conditions and optoelectrical properties of thin film material consisting of regularly ordered core/shell Ge/Al and Ge/SiN/Al quantum dots (QDs) in an alumina matrix. The materials were produced by self-assembled growth achieved by means of multilayer magnetron sputtering deposition. We demonstrated the successful fabrication of well-ordered 3D lattices of Ge/Al and Ge/SiN/Al core/shell quantum dots with a body-centred tetragonal arrangement within the AlO matrix.
View Article and Find Full Text PDFNanomaterials (Basel)
March 2021
Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
Controllable growth of wafer-scale in-plane nanowires (NWs) is a prerequisite for achieving addressable and scalable NW-based quantum devices. Here, by introducing molecular beam epitaxy on patterned Si structures, we demonstrate the wafer-scale epitaxial growth of site-controlled in-plane Si, SiGe, and Ge/Si core/shell NW arrays on Si (001) substrate. The epitaxially grown Si, SiGe, and Ge/Si core/shell NW are highly homogeneous with well-defined facets.
View Article and Find Full Text PDFLangmuir
January 2021
School of Chemistry, Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel.
Here, we propose a novel method for the synthesis of extremely uniform, diversely doped silicon nanotube heterostructures. The method, comprising a simple two-step synthesis, exploits the use of a Ge nanowire sacrificial core upon which a multidoping axial pattern can be easily obtained, that is enclosed in an intrinsic Si shell. The Ge-Si core-shell structure is then heated to 750 °C, allowing the migration of dopant elements from the Ge core directly into the Si shell.
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