Tunnel barrier design in donor nanostructures defined by hydrogen-resist lithography
A four-terminal donor quantum dot (QD) is used to characterize potential barriers between degenerately doped nanoscale contacts. The QD is fabricated by hydrogen-resist lithography on Si(001) in combination with n -type doping by phosphine. The four contacts have different separations ( d = 9, 12,...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2016-01-01
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| Series: | New Journal of Physics |
| Online Access: | https://doi.org/10.1088/1367-2630/18/8/083001 |
| _version_ | 1797751032108810240 |
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| author | Nikola Pascher Szymon Hennel Susanne Mueller Andreas Fuhrer |
| author_facet | Nikola Pascher Szymon Hennel Susanne Mueller Andreas Fuhrer |
| author_sort | Nikola Pascher |
| collection | DOAJ |
| description | A four-terminal donor quantum dot (QD) is used to characterize potential barriers between degenerately doped nanoscale contacts. The QD is fabricated by hydrogen-resist lithography on Si(001) in combination with n -type doping by phosphine. The four contacts have different separations ( d = 9, 12, 16 and 29 nm) to the central 6 nm × 6 nm QD island, leading to different tunnel and capacitive coupling. Cryogenic transport measurements in the Coulomb-blockade (CB) regime are used to characterize these tunnel barriers. We find that field enhancement near the apex of narrow dopant leads is an important effect that influences both barrier breakdown and the magnitude of the tunnel current in the CB transport regime. From CB-spectroscopy measurements, we extract the mutual capacitances between the QD and the four contacts, which scale inversely with the contact separation d . The capacitances are in excellent agreement with numerical values calculated from the pattern geometry in the hydrogen resist. Furthermore, we show that by engineering the source–drain tunnel barriers to be asymmetric, we obtain a much simpler excited-state spectrum of the QD, which can be directly linked to the orbital single-particle spectrum. |
| first_indexed | 2024-03-12T16:41:28Z |
| format | Article |
| id | doaj.art-69e96d7c93f14a03bc34d80524e507c5 |
| institution | Directory Open Access Journal |
| issn | 1367-2630 |
| language | English |
| last_indexed | 2024-03-12T16:41:28Z |
| publishDate | 2016-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | New Journal of Physics |
| spelling | doaj.art-69e96d7c93f14a03bc34d80524e507c52023-08-08T14:27:44ZengIOP PublishingNew Journal of Physics1367-26302016-01-0118808300110.1088/1367-2630/18/8/083001Tunnel barrier design in donor nanostructures defined by hydrogen-resist lithographyNikola Pascher0Szymon Hennel1Susanne Mueller2Andreas Fuhrer3IBM Research—Zurich , Säumerstrasse 4, 8803 Rüschlikon, SwitzerlandSolid State Physics Laboratory , ETH Zurich, 8093 Zurich, SwitzerlandSolid State Physics Laboratory , ETH Zurich, 8093 Zurich, SwitzerlandIBM Research—Zurich , Säumerstrasse 4, 8803 Rüschlikon, SwitzerlandA four-terminal donor quantum dot (QD) is used to characterize potential barriers between degenerately doped nanoscale contacts. The QD is fabricated by hydrogen-resist lithography on Si(001) in combination with n -type doping by phosphine. The four contacts have different separations ( d = 9, 12, 16 and 29 nm) to the central 6 nm × 6 nm QD island, leading to different tunnel and capacitive coupling. Cryogenic transport measurements in the Coulomb-blockade (CB) regime are used to characterize these tunnel barriers. We find that field enhancement near the apex of narrow dopant leads is an important effect that influences both barrier breakdown and the magnitude of the tunnel current in the CB transport regime. From CB-spectroscopy measurements, we extract the mutual capacitances between the QD and the four contacts, which scale inversely with the contact separation d . The capacitances are in excellent agreement with numerical values calculated from the pattern geometry in the hydrogen resist. Furthermore, we show that by engineering the source–drain tunnel barriers to be asymmetric, we obtain a much simpler excited-state spectrum of the QD, which can be directly linked to the orbital single-particle spectrum.https://doi.org/10.1088/1367-2630/18/8/083001 |
| spellingShingle | Nikola Pascher Szymon Hennel Susanne Mueller Andreas Fuhrer Tunnel barrier design in donor nanostructures defined by hydrogen-resist lithography New Journal of Physics |
| title | Tunnel barrier design in donor nanostructures defined by hydrogen-resist lithography |
| title_full | Tunnel barrier design in donor nanostructures defined by hydrogen-resist lithography |
| title_fullStr | Tunnel barrier design in donor nanostructures defined by hydrogen-resist lithography |
| title_full_unstemmed | Tunnel barrier design in donor nanostructures defined by hydrogen-resist lithography |
| title_short | Tunnel barrier design in donor nanostructures defined by hydrogen-resist lithography |
| title_sort | tunnel barrier design in donor nanostructures defined by hydrogen resist lithography |
| url | https://doi.org/10.1088/1367-2630/18/8/083001 |
| work_keys_str_mv | AT nikolapascher tunnelbarrierdesignindonornanostructuresdefinedbyhydrogenresistlithography AT szymonhennel tunnelbarrierdesignindonornanostructuresdefinedbyhydrogenresistlithography AT susannemueller tunnelbarrierdesignindonornanostructuresdefinedbyhydrogenresistlithography AT andreasfuhrer tunnelbarrierdesignindonornanostructuresdefinedbyhydrogenresistlithography |