Fabrication of quantum dots in undoped Si/Si0.8Ge0.2 heterostructures using a single metal-gate layer
| Autor: | Joel R. Wendt, Michael Lilly, Erik Nielsen, Michael C. Wanke, Malcolm S. Carroll, D. Bethke, G. A. Ten Eyck, Tzu-Ming Lu, John King Gamble, Richard P. Muller, Jason Dominguez, Tammy Pluym |
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| Rok vydání: | 2016 |
| Předmět: |
010302 applied physics
Materials science Fabrication Condensed Matter - Mesoscale and Nanoscale Physics Physics and Astronomy (miscellaneous) business.industry FOS: Physical sciences Heterojunction 02 engineering and technology Electron Condensed Matter::Mesoscopic Systems and Quantum Hall Effect 021001 nanoscience & nanotechnology 01 natural sciences Threshold voltage Nanolithography Quantum dot Mesoscale and Nanoscale Physics (cond-mat.mes-hall) 0103 physical sciences Optoelectronics 0210 nano-technology business Metal gate Quantum computer |
| Zdroj: | Applied Physics Letters. 109:093102 |
| ISSN: | 1077-3118 0003-6951 |
| DOI: | 10.1063/1.4961889 |
| Popis: | Enhancement-mode Si/SiGe electron quantum dots have been pursued extensively by many groups for \revEdit{their} potential in quantum computing. Most of the reported dot designs utilize multiple metal-gate layers and use Si/SiGe heterostructures with Ge concentration close to 30\%. Here we report the fabrication and low-temperature characterization of quantum dots in Si/Si$_{0.8}$Ge$_{0.2}$ heterostructures using only one metal-gate layer. We find that the threshold voltage of a channel narrower than 1 $\mu$m increases as the width decreases. The higher threshold can be attributed to the combination of quantum confinement and disorder. We also find that the lower Ge ratio used here leads to a narrower operational gate bias range. The higher threshold combined with the limited gate bias range constrains the device design of lithographic quantum dots. We incorporate such considerations in our device design and demonstrate a quantum dot that can be tuned from a single dot to a double dot. The device uses only a single metal-gate layer, greatly simplifying device design and fabrication. |
| Databáze: | OpenAIRE |
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