1
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Gao H, Kong ZZ, Zhang P, Luo Y, Su H, Liu XF, Wang GL, Wang JY, Xu HQ. Gate-defined quantum point contacts in a germanium quantum well. NANOSCALE 2024; 16:10333-10339. [PMID: 38738596 DOI: 10.1039/d4nr00712c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2024]
Abstract
We report an experimental study of quantum point contacts defined in a high-quality strained germanium quantum well with layered electric gates. At a zero magnetic field, we observed quantized conductance plateaus in units of 2e2/h. Bias-spectroscopy measurements reveal that the energy spacing between successive one-dimensional subbands ranges from 1.5 to 5 meV as a consequence of the small effective mass of the holes and the narrow gate constrictions. At finite magnetic fields perpendicular to the device plane, the edges of the conductance plateaus get split due to the Zeeman effect and Landé g factors were estimated to be ∼6.6 for the holes in the germanium quantum well. We demonstrate that all quantum point contacts in the same device have comparable performances, indicating a reliable and reproducible device fabrication process. Thus, our work lays a foundation for investigating multiple forefronts of physics in germanium-based quantum devices that require quantum point contacts as building blocks.
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Affiliation(s)
- Han Gao
- Beijing Key Laboratory of Quantum Devices, Key Laboratory for the Physics and Chemistry of Nanodevices, and School of Electronics, Peking University, Beijing 100871, China.
| | - Zhen-Zhen Kong
- Key Laboratory of Microelectronics Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China.
| | - Po Zhang
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China.
| | - Yi Luo
- Beijing Key Laboratory of Quantum Devices, Key Laboratory for the Physics and Chemistry of Nanodevices, and School of Electronics, Peking University, Beijing 100871, China.
- Institute of Condensed Matter and Material Physics, School of Physics, Peking University, Beijing 100871, China
| | - Haitian Su
- Beijing Key Laboratory of Quantum Devices, Key Laboratory for the Physics and Chemistry of Nanodevices, and School of Electronics, Peking University, Beijing 100871, China.
- Institute of Condensed Matter and Material Physics, School of Physics, Peking University, Beijing 100871, China
| | - Xiao-Fei Liu
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China.
| | - Gui-Lei Wang
- Key Laboratory of Microelectronics Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China.
- Hefei National Laboratory, University of Science and Technology of China, Hefei, Anhui 230088, China
- Beijing Superstring Academy of Memory Technology, Beijing 100176, China
| | - Ji-Yin Wang
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China.
| | - H Q Xu
- Beijing Key Laboratory of Quantum Devices, Key Laboratory for the Physics and Chemistry of Nanodevices, and School of Electronics, Peking University, Beijing 100871, China.
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China.
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2
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Valentini M, Sagi O, Baghumyan L, de Gijsel T, Jung J, Calcaterra S, Ballabio A, Aguilera Servin J, Aggarwal K, Janik M, Adletzberger T, Seoane Souto R, Leijnse M, Danon J, Schrade C, Bakkers E, Chrastina D, Isella G, Katsaros G. Parity-conserving Cooper-pair transport and ideal superconducting diode in planar germanium. Nat Commun 2024; 15:169. [PMID: 38167818 PMCID: PMC10762135 DOI: 10.1038/s41467-023-44114-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 11/30/2023] [Indexed: 01/05/2024] Open
Abstract
Superconductor/semiconductor hybrid devices have attracted increasing interest in the past years. Superconducting electronics aims to complement semiconductor technology, while hybrid architectures are at the forefront of new ideas such as topological superconductivity and protected qubits. In this work, we engineer the induced superconductivity in two-dimensional germanium hole gas by varying the distance between the quantum well and the aluminum. We demonstrate a hard superconducting gap and realize an electrically and flux tunable superconducting diode using a superconducting quantum interference device (SQUID). This allows to tune the current phase relation (CPR), to a regime where single Cooper pair tunneling is suppressed, creating a [Formula: see text] CPR. Shapiro experiments complement this interpretation and the microwave drive allows to create a diode with ≈ 100% efficiency. The reported results open up the path towards integration of spin qubit devices, microwave resonators and (protected) superconducting qubits on the same silicon technology compatible platform.
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Affiliation(s)
- Marco Valentini
- Institute of Science and Technology Austria, Klosterneuburg, Austria.
| | - Oliver Sagi
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Levon Baghumyan
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Thijs de Gijsel
- Institute of Science and Technology Austria, Klosterneuburg, Austria
- Department of Applied Physics, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Jason Jung
- Department of Applied Physics, Eindhoven University of Technology, Eindhoven, The Netherlands
| | | | - Andrea Ballabio
- L-NESS, Physics Department, Politecnico di Milano, Como, Italy
| | | | - Kushagra Aggarwal
- Institute of Science and Technology Austria, Klosterneuburg, Austria
- Department of Materials, University of Oxford, Oxford, UK
| | - Marian Janik
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | | | - Rubén Seoane Souto
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
- Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas (ICMM-CSIC), Madrid, Spain
| | - Martin Leijnse
- NanoLund and Solid State Physics, Lund University, Lund, Sweden
| | - Jeroen Danon
- Department of Physics, Norwegian University of Science and Technology, Trondheim, Norway
| | - Constantin Schrade
- Hearne Institute for Theoretical Physics, Department of Physics and Astronomy, Louisiana State University, Baton Rouge, USA
| | - Erik Bakkers
- Department of Applied Physics, Eindhoven University of Technology, Eindhoven, The Netherlands
| | | | - Giovanni Isella
- L-NESS, Physics Department, Politecnico di Milano, Como, Italy
| | - Georgios Katsaros
- Institute of Science and Technology Austria, Klosterneuburg, Austria.
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3
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Haxell DZ, Cheah E, Křížek F, Schott R, Ritter MF, Hinderling M, Belzig W, Bruder C, Wegscheider W, Riel H, Nichele F. Measurements of Phase Dynamics in Planar Josephson Junctions and SQUIDs. PHYSICAL REVIEW LETTERS 2023; 130:087002. [PMID: 36898094 DOI: 10.1103/physrevlett.130.087002] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 09/15/2022] [Accepted: 01/19/2023] [Indexed: 06/18/2023]
Abstract
We experimentally investigate the stochastic phase dynamics of planar Josephson junctions (JJs) and superconducting quantum interference devices (SQUIDs) defined in epitaxial InAs/Al heterostructures, and characterized by a large ratio of Josephson energy to charging energy. We observe a crossover from a regime of macroscopic quantum tunneling to one of phase diffusion as a function of temperature, where the transition temperature T^{*} is gate-tunable. The switching probability distributions are shown to be consistent with a small shunt capacitance and moderate damping, resulting in a switching current which is a small fraction of the critical current. Phase locking between two JJs leads to a difference in switching current between that of a JJ measured in isolation and that of the same JJ measured in an asymmetric SQUID loop. In the case of the loop, T^{*} is also tuned by a magnetic flux.
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Affiliation(s)
- D Z Haxell
- IBM Research Europe-Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - E Cheah
- Solid State Physics Laboratory, ETH Zurich, 8093 Zurich, Switzerland
| | - F Křížek
- IBM Research Europe-Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
- Solid State Physics Laboratory, ETH Zurich, 8093 Zurich, Switzerland
| | - R Schott
- Solid State Physics Laboratory, ETH Zurich, 8093 Zurich, Switzerland
| | - M F Ritter
- IBM Research Europe-Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - M Hinderling
- IBM Research Europe-Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - W Belzig
- Fachbereich Physik, Universität Konstanz, D-78457 Konstanz, Germany
| | - C Bruder
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - W Wegscheider
- Solid State Physics Laboratory, ETH Zurich, 8093 Zurich, Switzerland
| | - H Riel
- IBM Research Europe-Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - F Nichele
- IBM Research Europe-Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
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4
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Johnson BC, Stuiber M, Creedon DL, Bose M, Berhane A, Willems van Beveren LH, Rubanov S, Cole JH, Mourik V, Hamilton AR, Duty TL, McCallum JC. Silicon-Aluminum Phase-Transformation-Induced Superconducting Rings. NANO LETTERS 2023; 23:17-24. [PMID: 36573935 DOI: 10.1021/acs.nanolett.2c02814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The development of devices that exhibit both superconducting and semiconducting properties is an important endeavor for emerging quantum technologies. We investigate superconducting nanowires fabricated on a silicon-on-insulator (SOI) platform. Aluminum from deposited contact electrodes is found to interdiffuse with Si along the entire length of the nanowire, over micrometer length scales and at temperatures well below the Al-Si eutectic. The phase-transformed material is conformal with the predefined device patterns. The superconducting properties of a transformed mesoscopic ring formed on a SOI platform are investigated. Low-temperature magnetoresistance oscillations, quantized in units of the fluxoid, h/2e, are observed.
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Affiliation(s)
- Brett C Johnson
- School of Science, RMIT University, Melbourne, Victoria3001, Australia
| | - Michael Stuiber
- Melbourne Centre for Nanofabrication, Clayton, Victoria3168, Australia
| | - Daniel L Creedon
- School of Physics, University of Melbourne, Parkville, Victoria3010, Australia
| | - Manjith Bose
- School of Physics, University of Melbourne, Parkville, Victoria3010, Australia
| | - Amanuel Berhane
- School of Physics, University of New South Wales, Sydney, New South Wales1466, Australia
| | | | - Sergey Rubanov
- Ian Holmes Imaging Centre, Bio21 Institute, University of Melbourne, Parkville, Victoria3010, Australia
| | - Jared H Cole
- School of Science, RMIT University, Melbourne, Victoria3001, Australia
| | - Vincent Mourik
- School of Physics, University of New South Wales, Sydney, New South Wales1466, Australia
| | - Alexander R Hamilton
- School of Physics, University of New South Wales, Sydney, New South Wales1466, Australia
| | - Timothy L Duty
- School of Physics, University of New South Wales, Sydney, New South Wales1466, Australia
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5
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Wind L, Sistani M, Böckle R, Smoliner J, Vukŭsić L, Aberl J, Brehm M, Schweizer P, Maeder X, Michler J, Fournel F, Hartmann JM, Weber WM. Composition Dependent Electrical Transport in Si 1-x Ge x Nanosheets with Monolithic Single-Elementary Al Contacts. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2204178. [PMID: 36135726 DOI: 10.1002/smll.202204178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/25/2022] [Indexed: 06/16/2023]
Abstract
Si1-x Gex is a key material in modern complementary metal-oxide-semiconductor and bipolar devices. However, despite considerable efforts in metal-silicide and -germanide compound material systems, reliability concerns have so far hindered the implementation of metal-Si1-x Gex junctions that are vital for diverse emerging "More than Moore" and quantum computing paradigms. In this respect, the systematic structural and electronic properties of Al-Si1-x Gex heterostructures, obtained from a thermally induced exchange between ultra-thin Si1-x Gex nanosheets and Al layers are reported. Remarkably, no intermetallic phases are found after the exchange process. Instead, abrupt, flat, and void-free junctions of high structural quality can be obtained. Interestingly, ultra-thin interfacial Si layers are formed between the metal and Si1-x Gex segments, explaining the morphologic stability. Integrated into omega-gated Schottky barrier transistors with the channel length being defined by the selective transformation of Si1-x Gex into single-elementary Al leads, a detailed analysis of the transport is conducted. In this respect, a report on a highly versatile platform with Si1-x Gex composition-dependent properties ranging from highly transparent contacts to distinct Schottky barriers is provided. Most notably, the presented abrupt, robust, and reliable metal-Si1-x Gex junctions can open up new device implementations for different types of emerging nanoelectronic, optoelectronic, and quantum devices.
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Affiliation(s)
- Lukas Wind
- Institute of Solid State Electronics, Technische Universität Wien, Gußhausstraße 25-25a, Vienna, 1040, Austria
| | - Masiar Sistani
- Institute of Solid State Electronics, Technische Universität Wien, Gußhausstraße 25-25a, Vienna, 1040, Austria
| | - Raphael Böckle
- Institute of Solid State Electronics, Technische Universität Wien, Gußhausstraße 25-25a, Vienna, 1040, Austria
| | - Jürgen Smoliner
- Institute of Solid State Electronics, Technische Universität Wien, Gußhausstraße 25-25a, Vienna, 1040, Austria
| | - Lada Vukŭsić
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University, Altenberger Straße 69, Linz, 4040, Austria
| | - Johannes Aberl
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University, Altenberger Straße 69, Linz, 4040, Austria
| | - Moritz Brehm
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University, Altenberger Straße 69, Linz, 4040, Austria
| | - Peter Schweizer
- Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Mechanics of Materials and Nanostructures, Feuerwerkstrasse 39, Thun, 3602, Switzerland
| | - Xavier Maeder
- Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Mechanics of Materials and Nanostructures, Feuerwerkstrasse 39, Thun, 3602, Switzerland
| | - Johann Michler
- Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Mechanics of Materials and Nanostructures, Feuerwerkstrasse 39, Thun, 3602, Switzerland
| | - Frank Fournel
- CEA-LETI, University Grenoble Alpes, 17 Avenue des Martyrs, Grenoble, 38000, France
| | - Jean-Michel Hartmann
- CEA-LETI, University Grenoble Alpes, 17 Avenue des Martyrs, Grenoble, 38000, France
| | - Walter M Weber
- Institute of Solid State Electronics, Technische Universität Wien, Gußhausstraße 25-25a, Vienna, 1040, Austria
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6
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Delaforce J, Sistani M, Kramer RBG, Luong MA, Roch N, Weber WM, den Hertog MI, Robin E, Naud C, Lugstein A, Buisson O. Al-Ge-Al Nanowire Heterostructure: From Single-Hole Quantum Dot to Josephson Effect. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2101989. [PMID: 34365674 DOI: 10.1002/adma.202101989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 05/31/2021] [Indexed: 06/13/2023]
Abstract
Superconductor-semiconductor-superconductor heterostructures are attractive for both fundamental studies of quantum phenomena in low-dimensional hybrid systems as well as for future high-performance low power dissipating nanoelectronic and quantum devices. In this work, ultrascaled monolithic Al-Ge-Al nanowire heterostructures featuring monocrystalline Al leads and abrupt metal-semiconductor interfaces are used to probe the low-temperature transport in intrinsic Ge (i-Ge) quantum dots. In particular, demonstrating the ability to tune the Ge quantum dot device from completely insulating, through a single-hole-filling quantum dot regime, to a supercurrent regime, resembling a Josephson field effect transistor with a maximum critical current of 10 nA at a temperature of 390 mK. The realization of a Josephson field-effect transistor with high junction transparency provides a mechanism to study sub-gap transport mediated by Andreev states. The presented results reveal a promising intrinsic Ge-based architecture for hybrid superconductor-semiconductor devices for the study of Majorana zero modes and key components of quantum computing such as gatemons or gate tunable superconducting quantum interference devices.
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Affiliation(s)
- Jovian Delaforce
- Institut NEEL UPR2940, Université Grenoble Alpes, CNRS, Grenoble, 38042, France
| | - Masiar Sistani
- Institute of Solid State Electronics, TU Wien, Gußhausstraße 25-25a, Vienna, 1040, Austria
| | - Roman B G Kramer
- Institut NEEL UPR2940, Université Grenoble Alpes, CNRS, Grenoble, 38042, France
| | - Minh A Luong
- Université Grenoble Alpes, CEA, IRIG-DEPHY, F-38054, Grenoble, 38054, France
| | - Nicolas Roch
- Institut NEEL UPR2940, Université Grenoble Alpes, CNRS, Grenoble, 38042, France
| | - Walter M Weber
- Institute of Solid State Electronics, TU Wien, Gußhausstraße 25-25a, Vienna, 1040, Austria
| | | | - Eric Robin
- Université Grenoble Alpes, CEA, IRIG-DEPHY, F-38054, Grenoble, 38054, France
| | - Cecile Naud
- Institut NEEL UPR2940, Université Grenoble Alpes, CNRS, Grenoble, 38042, France
| | - Alois Lugstein
- Institute of Solid State Electronics, TU Wien, Gußhausstraße 25-25a, Vienna, 1040, Austria
| | - Olivier Buisson
- Institut NEEL UPR2940, Université Grenoble Alpes, CNRS, Grenoble, 38042, France
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7
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Jirovec D, Hofmann A, Ballabio A, Mutter PM, Tavani G, Botifoll M, Crippa A, Kukucka J, Sagi O, Martins F, Saez-Mollejo J, Prieto I, Borovkov M, Arbiol J, Chrastina D, Isella G, Katsaros G. A singlet-triplet hole spin qubit in planar Ge. NATURE MATERIALS 2021; 20:1106-1112. [PMID: 34083775 DOI: 10.1038/s41563-021-01022-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 04/23/2021] [Indexed: 06/12/2023]
Abstract
Spin qubits are considered to be among the most promising candidates for building a quantum processor. Group IV hole spin qubits are particularly interesting owing to their ease of operation and compatibility with Si technology. In addition, Ge offers the option for monolithic superconductor-semiconductor integration. Here, we demonstrate a hole spin qubit operating at fields below 10 mT, the critical field of Al, by exploiting the large out-of-plane hole g-factors in planar Ge and by encoding the qubit into the singlet-triplet states of a double quantum dot. We observe electrically controlled g-factor difference-driven and exchange-driven rotations with tunable frequencies exceeding 100 MHz and dephasing times of 1 μs, which we extend beyond 150 μs using echo techniques. These results demonstrate that Ge hole singlet-triplet qubits are competing with state-of-the-art GaAs and Si singlet-triplet qubits. In addition, their rotation frequencies and coherence are comparable with those of Ge single spin qubits, but singlet-triplet qubits can be operated at much lower fields, emphasizing their potential for on-chip integration with superconducting technologies.
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Affiliation(s)
- Daniel Jirovec
- Institute of Science and Technology Austria, Klosterneuburg, Austria.
| | - Andrea Hofmann
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Andrea Ballabio
- Laboratory for Epitaxial Nanostructures on Silicon and Spintronics, Physics Department, Politecnico di Milano, Como, Italy
| | - Philipp M Mutter
- Department of Physics, University of Konstanz, Konstanz, Germany
| | - Giulio Tavani
- Laboratory for Epitaxial Nanostructures on Silicon and Spintronics, Physics Department, Politecnico di Milano, Como, Italy
| | - Marc Botifoll
- Catalan Institute of Nanoscience and Nanotechnology, Spanish National Research Council, Barcelona Institute of Science and Technology, Autonomous University of Barcelona, Barcelona, Spain
| | - Alessandro Crippa
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Josip Kukucka
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Oliver Sagi
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Frederico Martins
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | | | - Ivan Prieto
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Maksim Borovkov
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Jordi Arbiol
- Catalan Institute of Nanoscience and Nanotechnology, Spanish National Research Council, Barcelona Institute of Science and Technology, Autonomous University of Barcelona, Barcelona, Spain
- Catalan Institution for Research and Advanced Studies, Barcelona, Spain
| | - Daniel Chrastina
- Laboratory for Epitaxial Nanostructures on Silicon and Spintronics, Physics Department, Politecnico di Milano, Como, Italy
| | - Giovanni Isella
- Laboratory for Epitaxial Nanostructures on Silicon and Spintronics, Physics Department, Politecnico di Milano, Como, Italy
| | - Georgios Katsaros
- Institute of Science and Technology Austria, Klosterneuburg, Austria.
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8
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Wind L, Sistani M, Song Z, Maeder X, Pohl D, Michler J, Rellinghaus B, Weber WM, Lugstein A. Monolithic Metal-Semiconductor-Metal Heterostructures Enabling Next-Generation Germanium Nanodevices. ACS APPLIED MATERIALS & INTERFACES 2021; 13:12393-12399. [PMID: 33683092 PMCID: PMC7975277 DOI: 10.1021/acsami.1c00502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Accepted: 02/23/2021] [Indexed: 06/12/2023]
Abstract
Low-dimensional Ge is perceived as a promising building block for emerging optoelectronic devices. Here, we present a wafer-scale platform technology enabling monolithic Al-Ge-Al nanostructures fabricated by a thermally induced Al-Ge exchange reaction. Transmission electron microscopy confirmed the purity and crystallinity of the formed Al segments with an abrupt interface to the remaining Ge segment. In good agreement with the theoretical value of bulk Al-Ge Schottky junctions, a barrier height of 200 ± 20 meV was determined. Photoluminescence and μ-Raman measurements proved the optical quality of the Ge channel embedded in the monolithic Al-Ge-Al heterostructure. Together with the wafer-scale accessibility, the proposed fabrication scheme may give rise to the development of key components of a broad spectrum of emerging Ge-based devices requiring monolithic metal-semiconductor-metal heterostructures with high-quality interfaces.
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Affiliation(s)
- Lukas Wind
- Institute
of Solid State Electronics, Technische Universität
Wien, Gußhausstraße 25-25a, Vienna 1040, Austria
| | - Masiar Sistani
- Institute
of Solid State Electronics, Technische Universität
Wien, Gußhausstraße 25-25a, Vienna 1040, Austria
| | - Zehao Song
- Institute
of Solid State Electronics, Technische Universität
Wien, Gußhausstraße 25-25a, Vienna 1040, Austria
| | - Xavier Maeder
- Swiss
Federal Laboratories for Materials Science and Technology, Laboratory for Mechanics of Materials and Nanostructures, Feuerwerkerstrasse 39, Thun 3602, Switzerland
| | - Darius Pohl
- Dresden
Center for Nanoanalysis, Technische Universität
Dresden, Helmholtzstraße
18, Dresden 01069, Germany
| | - Johann Michler
- Swiss
Federal Laboratories for Materials Science and Technology, Laboratory for Mechanics of Materials and Nanostructures, Feuerwerkerstrasse 39, Thun 3602, Switzerland
| | - Bernd Rellinghaus
- Dresden
Center for Nanoanalysis, Technische Universität
Dresden, Helmholtzstraße
18, Dresden 01069, Germany
| | - Walter M. Weber
- Institute
of Solid State Electronics, Technische Universität
Wien, Gußhausstraße 25-25a, Vienna 1040, Austria
| | - Alois Lugstein
- Institute
of Solid State Electronics, Technische Universität
Wien, Gußhausstraße 25-25a, Vienna 1040, Austria
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9
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Tan S. Transmission Electron Microscopy: Applications in Nanotechnology. IEEE NANOTECHNOLOGY MAGAZINE 2021. [DOI: 10.1109/mnano.2020.3037432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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10
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Liu Z. A new method for fabrication and electrical characterization of nanosized molten metals. NANOTECHNOLOGY 2020; 31:445705. [PMID: 32707566 DOI: 10.1088/1361-6528/aba92c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The electric properties represent one of the most fundamental physical properties of a material. Here, we propose a two-probe based method for the rapid electrical characterization of molten metals. By in-situ forming a liquid bridge and tuning its size, the resistivity of the molten metal is directly determined, without the generally required electrode fabrication and free from the effect of contact resistances. Most critically, the proposed method allows for detecting and studying the changing of atomic structure such as solid-liquid phase transition on the nanoscale. As an applied example, the resistivity of molten Pt and the resistivity difference between solid Pt at room temperature and molten Pt are determined as [Formula: see text] Ω m and [Formula: see text] Ω m, respectively.
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Affiliation(s)
- Ze Liu
- Department of Engineering Mechanics, School of Civil Engineering, Wuhan University, Wuhan 430072, People's Republic of China. State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan 430072, People's Republic of China. Key Laboratory of Safety for Geotechnical and Structural Engineering of Hubei Province, School of Civil Engineering, Wuhan University, Wuhan 430072, People's Republic of China
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11
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Hendrickx NW, Lawrie WIL, Petit L, Sammak A, Scappucci G, Veldhorst M. A single-hole spin qubit. Nat Commun 2020; 11:3478. [PMID: 32651363 PMCID: PMC7351715 DOI: 10.1038/s41467-020-17211-7] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 06/16/2020] [Indexed: 11/09/2022] Open
Abstract
Qubits based on quantum dots have excellent prospects for scalable quantum technology due to their compatibility with standard semiconductor manufacturing. While early research focused on the simpler electron system, recent demonstrations using multi-hole quantum dots illustrated the favourable properties holes can offer for fast and scalable quantum control. Here, we establish a single-hole spin qubit in germanium and demonstrate the integration of single-shot readout and quantum control. We deplete a planar germanium double quantum dot to the last hole, confirmed by radio-frequency reflectrometry charge sensing. To demonstrate the integration of single-shot readout and qubit operation, we show Rabi driving on both qubits. We find remarkable electric control over the qubit resonance frequencies, providing great qubit addressability. Finally, we analyse the spin relaxation time, which we find to exceed one millisecond, setting the benchmark for hole quantum dot qubits. The ability to coherently manipulate a single hole spin underpins the quality of strained germanium and defines an excellent starting point for the construction of quantum hardware. While most results so far in semiconductor spin-based quantum computation use electron spins, devices based on hole spins may have more favourable properties for quantum applications. Here, the authors demonstrate single-shot readout and coherent control of a qubit made from a single hole spin.
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Affiliation(s)
- N W Hendrickx
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, P. O. Box 5046, 2600 GA, Delft, The Netherlands.
| | - W I L Lawrie
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, P. O. Box 5046, 2600 GA, Delft, The Netherlands
| | - L Petit
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, P. O. Box 5046, 2600 GA, Delft, The Netherlands
| | - A Sammak
- QuTech and Netherlands Organisation for Applied Scientific Research (TNO), Stieltjesweg 1, 2628 CK, Delft, The Netherlands
| | - G Scappucci
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, P. O. Box 5046, 2600 GA, Delft, The Netherlands
| | - M Veldhorst
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, P. O. Box 5046, 2600 GA, Delft, The Netherlands.
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Sistani M, Delaforce J, Kramer RBG, Roch N, Luong MA, den Hertog MI, Robin E, Smoliner J, Yao J, Lieber CM, Naud C, Lugstein A, Buisson O. Highly Transparent Contacts to the 1D Hole Gas in Ultrascaled Ge/Si Core/Shell Nanowires. ACS NANO 2019; 13:14145-14151. [PMID: 31816231 DOI: 10.1021/acsnano.9b06809] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Semiconductor-superconductor hybrid systems have outstanding potential for emerging high-performance nanoelectronics and quantum devices. However, critical to their successful application is the fabrication of high-quality and reproducible semiconductor-superconductor interfaces. Here, we realize and measure axial Al-Ge-Al nanowire heterostructures with atomically precise interfaces, enwrapped by an ultrathin epitaxial Si layer further denoted as Al-Ge/Si-Al nanowire heterostructures. The heterostructures were synthesized by a thermally induced exchange reaction of single-crystalline Ge/Si core/shell nanowires and lithographically defined Al contact pads. Applying this heterostructure formation scheme enables self-aligned quasi one-dimensional crystalline Al leads contacting ultrascaled Ge/Si segments with contact transparencies greater than 96%. Integration into back-gated field-effect devices and continuous scaling beyond lithographic limitations allows us to exploit the full potential of the highly transparent contacts to the 1D hole gas at the Ge-Si interface. This leads to the observation of ballistic transport as well as quantum confinement effects up to temperatures of 150 K. Low-temperature measurements reveal proximity-induced superconductivity in the Ge/Si core/shell nanowires. The realization of a Josephson field-effect transistor allows us to study the subgap structure caused by multiple Andreev reflections. Most importantly, the absence of a quantum dot regime indicates a hard superconducting gap originating from the highly transparent contacts to the 1D hole gas, which is potentially interesting for the study of Majorana zero modes. Moreover, underlining the importance of the proposed thermally induced Al-Ge/Si-Al heterostructure formation technique, our system could contribute to the development of key components of quantum computing such as gatemon or transmon qubits.
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Affiliation(s)
- Masiar Sistani
- Institute of Solid State Electronics, TU Wien , Gußhausstraße 25-25a , 1040 Vienna , Austria
| | - Jovian Delaforce
- Université Grenoble Alpes, CNRS, Institut NEEL UPR2940 , F-38054 Grenoble , France
| | - Roman B G Kramer
- Université Grenoble Alpes, CNRS, Institut NEEL UPR2940 , F-38054 Grenoble , France
| | - Nicolas Roch
- Université Grenoble Alpes, CNRS, Institut NEEL UPR2940 , F-38054 Grenoble , France
| | - Minh Anh Luong
- Université Grenoble Alpes, CEA, IRIG-DEPHY , F-38054 Grenoble , France
| | - Martien I den Hertog
- Université Grenoble Alpes, CNRS, Institut NEEL UPR2940 , F-38054 Grenoble , France
| | - Eric Robin
- Université Grenoble Alpes, CEA, IRIG-DEPHY , F-38054 Grenoble , France
| | - Jürgen Smoliner
- Institute of Solid State Electronics, TU Wien , Gußhausstraße 25-25a , 1040 Vienna , Austria
| | - Jun Yao
- Department of Electrical and Computer Engineering, Institute for Applied Life Sciences , University of Massachusetts , Amherst , Massachusetts 01003 , United States
| | - Charles M Lieber
- Department of Chemistry and Chemical Biology , Harvard University , Cambridge , Massachusetts 02138 , United States
- School of Engineering and Applied Science , Harvard University , Cambridge , Massachusetts 02138 , United States
| | - Cecile Naud
- Université Grenoble Alpes, CNRS, Institut NEEL UPR2940 , F-38054 Grenoble , France
| | - Alois Lugstein
- Institute of Solid State Electronics, TU Wien , Gußhausstraße 25-25a , 1040 Vienna , Austria
| | - Olivier Buisson
- Université Grenoble Alpes, CNRS, Institut NEEL UPR2940 , F-38054 Grenoble , France
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Passian A, Imam N. Nanosystems, Edge Computing, and the Next Generation Computing Systems. SENSORS (BASEL, SWITZERLAND) 2019; 19:E4048. [PMID: 31546907 PMCID: PMC6767340 DOI: 10.3390/s19184048] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 09/11/2019] [Accepted: 09/16/2019] [Indexed: 12/24/2022]
Abstract
It is widely recognized that nanoscience and nanotechnology and their subfields, such as nanophotonics, nanoelectronics, and nanomechanics, have had a tremendous impact on recent advances in sensing, imaging, and communication, with notable developments, including novel transistors and processor architectures. For example, in addition to being supremely fast, optical and photonic components and devices are capable of operating across multiple orders of magnitude length, power, and spectral scales, encompassing the range from macroscopic device sizes and kW energies to atomic domains and single-photon energies. The extreme versatility of the associated electromagnetic phenomena and applications, both classical and quantum, are therefore highly appealing to the rapidly evolving computing and communication realms, where innovations in both hardware and software are necessary to meet the growing speed and memory requirements. Development of all-optical components, photonic chips, interconnects, and processors will bring the speed of light, photon coherence properties, field confinement and enhancement, information-carrying capacity, and the broad spectrum of light into the high-performance computing, the internet of things, and industries related to cloud, fog, and recently edge computing. Conversely, owing to their extraordinary properties, 0D, 1D, and 2D materials are being explored as a physical basis for the next generation of logic components and processors. Carbon nanotubes, for example, have been recently used to create a new processor beyond proof of principle. These developments, in conjunction with neuromorphic and quantum computing, are envisioned to maintain the growth of computing power beyond the projected plateau for silicon technology. We survey the qualitative figures of merit of technologies of current interest for the next generation computing with an emphasis on edge computing.
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Affiliation(s)
- Ali Passian
- Computing & Computational Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA.
| | - Neena Imam
- Computing & Computational Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA.
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