1
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Ramanandan SP, Reñé Sapera J, Morelle A, Martí-Sánchez S, Rudra A, Arbiol J, Dubrovskii VG, Fontcuberta I Morral A. Control of Ge island coalescence for the formation of nanowires on silicon. NANOSCALE HORIZONS 2024; 9:555-565. [PMID: 38353654 PMCID: PMC10962639 DOI: 10.1039/d3nh00573a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 02/05/2024] [Indexed: 03/26/2024]
Abstract
Germanium nanowires could be the building blocks of hole-spin qubit quantum computers. Selective area epitaxy enables the direct integration of Ge nanowires on a silicon chip while controlling the device design, density, and scalability. For this to become a reality, it is essential to understand and control the initial stages of the epitaxy process. In this work, we highlight the importance of surface treatment in the reactor prior to growth to achieve high crystal quality and connected Ge nanowire structures. In particular, we demonstrate that exposure to AsH3 during the high-temperature treatment enhances lateral growth of initial Ge islands and promotes faster formation of continuous Ge nanowires in trenches. The Kolmogorov-Johnson-Mehl-Avrami crystallization model supports our explanation of Ge coalescence. These results provide critical insight into the selective epitaxy of horizontal Ge nanowires on lattice-mismatched Si substrates, which can be translated to other material systems.
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Affiliation(s)
- Santhanu Panikar Ramanandan
- Laboratory of Semiconductor Materials, Institute of Materials, Ecole Polytechnique Fédérale de Lausanne EPFL, Lausanne 1015, Switzerland.
| | - Joel Reñé Sapera
- Laboratory of Semiconductor Materials, Institute of Materials, Ecole Polytechnique Fédérale de Lausanne EPFL, Lausanne 1015, Switzerland.
| | - Alban Morelle
- Solid State Laboratory, ETH Zurich, 8093 Zurich, Switzerland
| | - Sara Martí-Sánchez
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, Barcelona, Catalonia, Spain
| | - Alok Rudra
- Laboratory of Semiconductor Materials, Institute of Materials, Ecole Polytechnique Fédérale de Lausanne EPFL, Lausanne 1015, Switzerland.
- Institute of Physics, Faculty of Basic Sciences, Ecole Polytechnique Fédérale de Lausanne EPFL, Lausanne 1015, Switzerland
| | - Jordi Arbiol
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, Barcelona, Catalonia, Spain
- ICREA, Pg. Lluís Companys 23, 08010 Barcelona, Catalonia, Spain
| | - Vladimir G Dubrovskii
- Faculty of Physics, St. Petersburg State University, Universitetskaya Embankment 13B, 199034 St. Petersburg, Russia
| | - Anna Fontcuberta I Morral
- Laboratory of Semiconductor Materials, Institute of Materials, Ecole Polytechnique Fédérale de Lausanne EPFL, Lausanne 1015, Switzerland.
- Institute of Physics, Faculty of Basic Sciences, Ecole Polytechnique Fédérale de Lausanne EPFL, Lausanne 1015, Switzerland
- Center for Quantum Science and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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2
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Peng K, Morgan NP, Wagner FM, Siday T, Xia CQ, Dede D, Boureau V, Piazza V, Fontcuberta I Morral A, Johnston MB. Direct and integrating sampling in terahertz receivers from wafer-scalable InAs nanowires. Nat Commun 2024; 15:103. [PMID: 38167839 PMCID: PMC10761983 DOI: 10.1038/s41467-023-44345-1] [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: 08/24/2023] [Accepted: 12/09/2023] [Indexed: 01/05/2024] Open
Abstract
Terahertz (THz) radiation will play a pivotal role in wireless communications, sensing, spectroscopy and imaging technologies in the decades to come. THz emitters and receivers should thus be simplified in their design and miniaturized to become a commodity. In this work we demonstrate scalable photoconductive THz receivers based on horizontally-grown InAs nanowires (NWs) embedded in a bow-tie antenna that work at room temperature. The NWs provide a short photoconductivity lifetime while conserving high electron mobility. The large surface-to-volume ratio also ensures low dark current and thus low thermal noise, compared to narrow-bandgap bulk devices. By engineering the NW morphology, the NWs exhibit greatly different photoconductivity lifetimes, enabling the receivers to detect THz photons via both direct and integrating sampling modes. The broadband NW receivers are compatible with gating lasers across the entire range of telecom wavelengths (1.2-1.6 μm) and thus are ideal for inexpensive all-optical fibre-based THz time-domain spectroscopy and imaging systems. The devices are deterministically positioned by lithography and thus scalable to the wafer scale, opening the path for a new generation of commercial THz receivers.
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Affiliation(s)
- Kun Peng
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, UK
| | - Nicholas Paul Morgan
- Laboratory of Semiconductor Materials, Institute of Materials, EPFL, 1015, Lausanne, Switzerland
| | - Ford M Wagner
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, UK
| | - Thomas Siday
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, UK
| | - Chelsea Qiushi Xia
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, UK
| | - Didem Dede
- Laboratory of Semiconductor Materials, Institute of Materials, EPFL, 1015, Lausanne, Switzerland
| | - Victor Boureau
- Interdisciplinary Centre for Electron Microscopy, EPFL, 1015, Lausanne, Switzerland
| | - Valerio Piazza
- Laboratory of Semiconductor Materials, Institute of Materials, EPFL, 1015, Lausanne, Switzerland
| | - Anna Fontcuberta I Morral
- Laboratory of Semiconductor Materials, Institute of Materials, EPFL, 1015, Lausanne, Switzerland.
- Laboratory of Semiconductor Materials, Institute of Physics, EPFL, 1015, Lausanne, Switzerland.
| | - Michael B Johnston
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, UK.
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3
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Morgan N, Dubrovskii VG, Stief AK, Dede D, Sanglé-Ferrière M, Rudra A, Piazza V, Fontcuberta i Morral A. From Layer-by-Layer Growth to Nanoridge Formation: Selective Area Epitaxy of GaAs by MOVPE. CRYSTAL GROWTH & DESIGN 2023; 23:5083-5092. [PMID: 37426543 PMCID: PMC10326851 DOI: 10.1021/acs.cgd.3c00316] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 06/01/2023] [Indexed: 07/11/2023]
Abstract
Selective area epitaxy at the nanoscale enables fabrication of high-quality nanostructures in regular arrays with predefined geometry. Here, we investigate the growth mechanisms of GaAs nanoridges on GaAs (100) substrates in selective area trenches by metal-organic vapor-phase epitaxy (MOVPE). It is found that pre-growth annealing results in the formation of valley-like structures of GaAs with atomic terraces inside the trenches. MOVPE growth of GaAs nanoridges consists of three distinct stages. Filling the trench in the first stage exhibits a step-flow growth behavior. Once the structure grows above the mask surface, it enters the second stage of growth by forming {101} side facets as the (100) flat top facet progressively shrinks. In the third stage, the fully formed nanoridge begins to overgrow onto the mask with a significantly reduced growth rate. We develop a kinetic model that accurately describes the width-dependent evolution of the nanoridge morphology through all three stages. MOVPE growth of fully formed nanoridges takes only about 1 min, which is 60 times faster than in our set of molecular beam epitaxy (MBE) experiments reported recently, and with a more regular, triangular cross-sectional geometry defined solely by the {101} facets. In contrast to MBE, no material loss due to Ga adatom diffusion onto the mask surface is observed in MOVPE until the third stage of growth. These results are useful for the fabrication of GaAs nanoridges of different dimensions on the same substrate for various applications and can be extended to other material systems.
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Affiliation(s)
- Nicholas Morgan
- Laboratory
of Semiconductor Materials, Institute of Materials, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Vladimir G. Dubrovskii
- Faculty
of Physics, Saint Petersburg State University, Universitetskaya Embankment 13B, 199034 St. Petersburg, Russia
| | - Ann-Kristin Stief
- Laboratory
of Semiconductor Materials, Institute of Materials, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Didem Dede
- Laboratory
of Semiconductor Materials, Institute of Materials, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Marie Sanglé-Ferrière
- Laboratory
of Semiconductor Materials, Institute of Materials, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Alok Rudra
- Laboratory
of Semiconductor Materials, Institute of Physics, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Valerio Piazza
- Laboratory
of Semiconductor Materials, Institute of Materials, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Anna Fontcuberta i Morral
- Laboratory
of Semiconductor Materials, Institute of Materials, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
- Laboratory
of Semiconductor Materials, Institute of Physics, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
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4
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Huang C, Dede D, Morgan N, Piazza V, Hu X, Fontcuberta I Morral A, Lauhon LJ. Trapping Layers Prevent Dopant Segregation and Enable Remote Doping of Templated Self-Assembled InGaAs Nanowires. NANO LETTERS 2023. [PMID: 37402180 PMCID: PMC10375592 DOI: 10.1021/acs.nanolett.3c00281] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/06/2023]
Abstract
Selective area epitaxy is a promising approach to define nanowire networks for topological quantum computing. However, it is challenging to concurrently engineer nanowire morphology, for carrier confinement, and precision doping, to tune carrier density. We report a strategy to promote Si dopant incorporation and suppress dopant diffusion in remote doped InGaAs nanowires templated by GaAs nanomembrane networks. Growth of a dilute AlGaAs layer following doping of the GaAs nanomembrane induces incorporation of Si that otherwise segregates to the growth surface, enabling precise control of the spacing between the Si donors and the undoped InGaAs channel; a simple model captures the influence of Al on the Si incorporation rate. Finite element modeling confirms that a high electron density is produced in the channel.
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Affiliation(s)
- Chunyi Huang
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Didem Dede
- Laboratory of Semiconductor Materials, Institute of Materials, EPFL, Route Cantonale, Lausanne, Vaud 1015, Switzerland
| | - Nicholas Morgan
- Laboratory of Semiconductor Materials, Institute of Materials, EPFL, Route Cantonale, Lausanne, Vaud 1015, Switzerland
| | - Valerio Piazza
- Laboratory of Semiconductor Materials, Institute of Materials, EPFL, Route Cantonale, Lausanne, Vaud 1015, Switzerland
| | - Xiaobing Hu
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
- The NUANCE Center, Northwestern University, Evanston, Illinois 60208, United States
| | - Anna Fontcuberta I Morral
- Laboratory of Semiconductor Materials, Institute of Materials, EPFL, Route Cantonale, Lausanne, Vaud 1015, Switzerland
| | - Lincoln J Lauhon
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
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5
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Qu J, Beznasyuk DV, Cassidy M, Tanta R, Yang L, Holmes NP, Griffith MJ, Krogstrup P, Cairney JM. Atomic-Scale Characterization of Planar Selective-Area-Grown InAs/InGaAs Nanowires. ACS APPLIED MATERIALS & INTERFACES 2022; 14:47981-47990. [PMID: 36222623 DOI: 10.1021/acsami.2c09594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Atomic-scale information about the structural and compositional properties of novel semiconductor nanowires is essential to tailoring their properties for specific applications, but characterization at this length scale remains a challenging task. Here, quasi-1D InAs/InGaAs semiconductor nanowire arrays were grown by selective area epitaxy (SAE) using molecular beam epitaxy (MBE), and their subsequent properties were analyzed by a combination of atom probe tomography (APT) and aberration-corrected transmission electron microscopy (TEM). Results revealed the chemical composition of the outermost thin InAs layer, a fine variation in the indium content at the InAs/InGaAs interface, and lightly incorporated element tracing. The results highlight the importance of correlative microscopy approaches in revealing complex nanoscale structures, with TEM being uniquely suited to interrogating the crystallography of InGaAs NWs, whereas APT is capable of three-dimensional (3D) elemental mapping, revealing the subtle compositional variation near the boundary region. This work demonstrates a detailed pathway for the nanoscale structural assessment of novel one-dimensional (1D) nanomaterials.
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Affiliation(s)
| | - Daria V Beznasyuk
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | | | - Rawa Tanta
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | | | | | | | - Peter Krogstrup
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
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6
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Dede D, Glas F, Piazza V, Morgan N, Friedl M, Güniat L, Nur Dayi E, Balgarkashi A, Dubrovskii VG, Fontcuberta I Morral A. Selective area epitaxy of GaAs: the unintuitive role of feature size and pitch. NANOTECHNOLOGY 2022; 33:485604. [PMID: 35952545 DOI: 10.1088/1361-6528/ac88d9] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 08/11/2022] [Indexed: 06/15/2023]
Abstract
Selective area epitaxy (SAE) provides the path for scalable fabrication of semiconductor nanostructures in a device-compatible configuration. In the current paradigm, SAE is understood as localized epitaxy, and is modelled by combining planar and self-assembled nanowire growth mechanisms. Here we use GaAs SAE as a model system to provide a different perspective. First, we provide evidence of the significant impact of the annealing stage in the calculation of the growth rates. Then, by elucidating the effect of geometrical constraints on the growth of the semiconductor crystal, we demonstrate the role of adatom desorption and resorption beyond the direct-impingement and diffusion-limited regime. Our theoretical model explains the effect of these constraints on the growth, and in particular why the SAE growth rate is highly sensitive to the pattern geometry. Finally, the disagreement of the model at the largest pitch points to non-negligible multiple adatom recycling between patterned features. Overall, our findings point out the importance of considering adatom diffusion, adsorption and desorption dynamics in designing the SAE pattern to create pre-determined nanoscale structures across a wafer. These results are fundamental for the SAE process to become viable in the semiconductor industry.
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Affiliation(s)
- Didem Dede
- Laboratory of Semiconductor Materials, Faculty of Engineering, Institute of Materials, EPFL, Lausanne, Switzerland
| | - Frank Glas
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, Palaiseau, France
| | - Valerio Piazza
- Laboratory of Semiconductor Materials, Faculty of Engineering, Institute of Materials, EPFL, Lausanne, Switzerland
| | - Nicholas Morgan
- Laboratory of Semiconductor Materials, Faculty of Engineering, Institute of Materials, EPFL, Lausanne, Switzerland
| | - Martin Friedl
- Laboratory of Semiconductor Materials, Faculty of Engineering, Institute of Materials, EPFL, Lausanne, Switzerland
| | - Lucas Güniat
- Laboratory of Semiconductor Materials, Faculty of Engineering, Institute of Materials, EPFL, Lausanne, Switzerland
| | - Elif Nur Dayi
- Laboratory of Semiconductor Materials, Faculty of Engineering, Institute of Materials, EPFL, Lausanne, Switzerland
| | - Akshay Balgarkashi
- Laboratory of Semiconductor Materials, Faculty of Engineering, Institute of Materials, EPFL, Lausanne, Switzerland
| | | | - Anna Fontcuberta I Morral
- Laboratory of Semiconductor Materials, Faculty of Engineering, Institute of Materials, EPFL, Lausanne, Switzerland
- Faculty of Basic Sciences, Institute of Physics, EPFL, Lausanne, Switzerland
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7
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Dubrovskii VG, Kim W, Piazza V, Güniat L, Fontcuberta I Morral A. Simultaneous Selective Area Growth of Wurtzite and Zincblende Self-Catalyzed GaAs Nanowires on Silicon. NANO LETTERS 2021; 21:3139-3145. [PMID: 33818097 DOI: 10.1021/acs.nanolett.1c00349] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Selective area epitaxy constitutes a mainstream method to obtain reproducible nanomaterials. As a counterpart, self-assembly allows their growth without costly substrate preparation, with the drawback of uncontrolled positioning. We propose a mixed approach in which self-assembly is limited to reduced regions on a patterned silicon substrate. While nanowires grow with a wide distribution of diameters, we note a mostly binary occurrence of crystal phases. Self-catalyzed GaAs nanowires form in either a wurtzite or zincblende phase in the same growth run. Quite surprisingly, thicker nanowires are wurtzite and thinner nanowires are zincblende, while the common view predicts the reverse trend. We relate this phenomenon to the influx of Ga adatoms by surface diffusion, which results in different contact angles of Ga droplets. We demonstrate the wurtzite phase of thick GaAs NWs up to 200 nm in diameter in the Au-free approach, which has not been achieved so far to our knowledge.
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Affiliation(s)
- Vladimir G Dubrovskii
- Faculty of Physics, St. Petersburg State University, Universitetskaya Embankment 13B, 199034 St. Petersburg, Russia
| | - Wonjong Kim
- Laboratory of Semiconductor Materials, Institute of Materials, Faculty of Engineering, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Valerio Piazza
- Laboratory of Semiconductor Materials, Institute of Materials, Faculty of Engineering, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Lucas Güniat
- Laboratory of Semiconductor Materials, Institute of Materials, Faculty of Engineering, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Anna Fontcuberta I Morral
- Laboratory of Semiconductor Materials, Institute of Materials, Faculty of Engineering, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
- Institute of Physics, Faculty of Basic Sciences, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
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8
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Gluschke JG, Seidl J, Tan HH, Jagadish C, Caroff P, Micolich AP. Impact of invasive metal probes on Hall measurements in semiconductor nanostructures. NANOSCALE 2020; 12:20317-20325. [PMID: 33006359 DOI: 10.1039/d0nr04402d] [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
Recent advances in bottom-up growth are giving rise to a range of new two-dimensional nanostructures. Hall effect measurements play an important role in their electrical characterization. However, size constraints can lead to device geometries that deviate significantly from the ideal of elongated Hall bars with currentless contacts. Many devices using these new materials have a low aspect ratio and feature metal Hall probes that overlap with the semiconductor channel. This can lead to a significant distortion of the current flow. We present experimental data from InAs 2D nanofin devices with different Hall probe geometries to study the influence of Hall probe length and width. We use finite-element simulations to further understand the implications of these aspects and expand their scope to contact resistance and sample aspect ratio. Our key finding is that invasive probes lead to significant underestimation of measured Hall voltage, typically of the order 40-80%. This in turn leads to a subsequent proportional overestimation of carrier concentration and an underestimation of mobility.
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Affiliation(s)
- Jan G Gluschke
- School of Physics, University of New South Wales, Sydney, NSW 2052, Australia.
| | - Jakob Seidl
- School of Physics, University of New South Wales, Sydney, NSW 2052, Australia.
| | - H Hoe Tan
- Department of Electronic Materials Engineering, Research School of Physics, The Australian National University, Canberra, ACT 2601, Australia
| | - Chennupati Jagadish
- Department of Electronic Materials Engineering, Research School of Physics, The Australian National University, Canberra, ACT 2601, Australia
| | - Philippe Caroff
- Department of Electronic Materials Engineering, Research School of Physics, The Australian National University, Canberra, ACT 2601, Australia and Microsoft Quantum Lab Delft, Delft University of Technology, 2600 GA, Delft, The Netherlands
| | - Adam P Micolich
- School of Physics, University of New South Wales, Sydney, NSW 2052, Australia.
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