1
|
Lu B, Xia Y, Ren Y, Xie M, Zhou L, Vinai G, Morton SA, Wee ATS, van der Wiel WG, Zhang W, Wong PKJ. When Machine Learning Meets 2D Materials: A Review. Adv Sci (Weinh) 2024; 11:e2305277. [PMID: 38279508 PMCID: PMC10987159 DOI: 10.1002/advs.202305277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 10/21/2023] [Indexed: 01/28/2024]
Abstract
The availability of an ever-expanding portfolio of 2D materials with rich internal degrees of freedom (spin, excitonic, valley, sublattice, and layer pseudospin) together with the unique ability to tailor heterostructures made layer by layer in a precisely chosen stacking sequence and relative crystallographic alignments, offers an unprecedented platform for realizing materials by design. However, the breadth of multi-dimensional parameter space and massive data sets involved is emblematic of complex, resource-intensive experimentation, which not only challenges the current state of the art but also renders exhaustive sampling untenable. To this end, machine learning, a very powerful data-driven approach and subset of artificial intelligence, is a potential game-changer, enabling a cheaper - yet more efficient - alternative to traditional computational strategies. It is also a new paradigm for autonomous experimentation for accelerated discovery and machine-assisted design of functional 2D materials and heterostructures. Here, the study reviews the recent progress and challenges of such endeavors, and highlight various emerging opportunities in this frontier research area.
Collapse
Affiliation(s)
- Bin Lu
- ARTIST Lab for Artificial Electronic Materials and Technologies, School of MicroelectronicsNorthwestern Polytechnical UniversityXi'an710072P. R. China
- Yangtze River Delta Research Institute of Northwestern Polytechnical UniversityTaicang215400P. R. China
| | - Yuze Xia
- ARTIST Lab for Artificial Electronic Materials and Technologies, School of MicroelectronicsNorthwestern Polytechnical UniversityXi'an710072P. R. China
- Yangtze River Delta Research Institute of Northwestern Polytechnical UniversityTaicang215400P. R. China
| | - Yuqian Ren
- ARTIST Lab for Artificial Electronic Materials and Technologies, School of MicroelectronicsNorthwestern Polytechnical UniversityXi'an710072P. R. China
- Yangtze River Delta Research Institute of Northwestern Polytechnical UniversityTaicang215400P. R. China
| | - Miaomiao Xie
- ARTIST Lab for Artificial Electronic Materials and Technologies, School of MicroelectronicsNorthwestern Polytechnical UniversityXi'an710072P. R. China
- Yangtze River Delta Research Institute of Northwestern Polytechnical UniversityTaicang215400P. R. China
| | - Liguo Zhou
- ARTIST Lab for Artificial Electronic Materials and Technologies, School of MicroelectronicsNorthwestern Polytechnical UniversityXi'an710072P. R. China
- Yangtze River Delta Research Institute of Northwestern Polytechnical UniversityTaicang215400P. R. China
| | - Giovanni Vinai
- Instituto Officina dei Materiali (IOM)‐CNRLaboratorio TASCTriesteI‐34149Italy
| | - Simon A. Morton
- Advanced Light Source (ALS)Lawrence Berkeley National LaboratoryBerkeleyCA94720USA
| | - Andrew T. S. Wee
- Department of Physics and Centre for Advanced 2D Materials (CA2DM) and Graphene Research Centre (GRC)National University of SingaporeSingapore117542Singapore
| | - Wilfred G. van der Wiel
- NanoElectronics Group, MESA+ Institute for Nanotechnology and BRAINS Center for Brain‐Inspired Nano SystemsUniversity of TwenteEnschede7500AEThe Netherlands
- Institute of PhysicsUniversity of Münster48149MünsterGermany
| | - Wen Zhang
- ARTIST Lab for Artificial Electronic Materials and Technologies, School of MicroelectronicsNorthwestern Polytechnical UniversityXi'an710072P. R. China
- Yangtze River Delta Research Institute of Northwestern Polytechnical UniversityTaicang215400P. R. China
- NanoElectronics Group, MESA+ Institute for Nanotechnology and BRAINS Center for Brain‐Inspired Nano SystemsUniversity of TwenteEnschede7500AEThe Netherlands
| | - Ping Kwan Johnny Wong
- ARTIST Lab for Artificial Electronic Materials and Technologies, School of MicroelectronicsNorthwestern Polytechnical UniversityXi'an710072P. R. China
- Yangtze River Delta Research Institute of Northwestern Polytechnical UniversityTaicang215400P. R. China
- NPU Chongqing Technology Innovation CenterChongqing400000P. R. China
| |
Collapse
|
2
|
Jaeger H, Noheda B, van der Wiel WG. Toward a formal theory for computing machines made out of whatever physics offers. Nat Commun 2023; 14:4911. [PMID: 37587135 PMCID: PMC10432384 DOI: 10.1038/s41467-023-40533-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Accepted: 08/01/2023] [Indexed: 08/18/2023] Open
Abstract
Approaching limitations of digital computing technologies have spurred research in neuromorphic and other unconventional approaches to computing. Here we argue that if we want to engineer unconventional computing systems in a systematic way, we need guidance from a formal theory that is different from the classical symbolic-algorithmic Turing machine theory. We propose a general strategy for developing such a theory, and within that general view, a specific approach that we call fluent computing. In contrast to Turing, who modeled computing processes from a top-down perspective as symbolic reasoning, we adopt the scientific paradigm of physics and model physical computing systems bottom-up by formalizing what can ultimately be measured in a physical computing system. This leads to an understanding of computing as the structuring of processes, while classical models of computing systems describe the processing of structures.
Collapse
Affiliation(s)
- Herbert Jaeger
- Bernoulli Institute, University of Groningen, 9700 AB, Groningen, The Netherlands.
- Groningen Cognitive Systems and Materials Center (CogniGron), University of Groningen, 9700 AB, Groningen, The Netherlands.
| | - Beatriz Noheda
- Groningen Cognitive Systems and Materials Center (CogniGron), University of Groningen, 9700 AB, Groningen, The Netherlands
- Zernike Institute for Advanced Materials, University of Groningen, 9700 AB, Groningen, The Netherlands
| | - Wilfred G van der Wiel
- BRAINS Center for Brain-Inspired Nano Systems, University of Twente, 7500 AE, Enschede, The Netherlands
- MESA+ Institute for Nanotechnology, University of Twente, 7500 AE, Enschede, The Netherlands
- Institute of Physics, Westfälische Wilhelms-Universität Münster, Münster, Germany
| |
Collapse
|
3
|
Usami Y, van de Ven B, Mathew DG, Chen T, Kotooka T, Kawashima Y, Tanaka Y, Otsuka Y, Ohoyama H, Tamukoh H, Tanaka H, van der Wiel WG, Matsumoto T. In-Materio Reservoir Computing in a Sulfonated Polyaniline Network. Adv Mater 2021; 33:e2102688. [PMID: 34533867 DOI: 10.1002/adma.202102688] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 08/22/2021] [Indexed: 06/13/2023]
Abstract
A sulfonated polyaniline (SPAN) organic electrochemical network device (OEND) is fabricated using a simple drop-casting method on multiple Au electrodes for use in reservoir computing (RC). The SPAN network has humidity-dependent electrical properties. Under high humidity, the SPAN OEND exhibits mainly ionic conduction, including charging of an electric double layer and ionic diffusion. The nonlinearity and hysteresis of the current-voltage characteristics progressively increase with increasing humidity. The rich dynamic output behavior indicates wide variations for each electrode, which improves the RC performance because of the disordered network. For RC, waveform generation and short-term memory tasks are realized by a linear combination of outputs. The waveform task accuracy and memory capacity calculated from a short-term memory task reach 90% and 33.9, respectively. Improved spoken-digit classification is realized with 60% accuracy by only 12 outputs, demonstrating that the SPAN OEND can manage time series dynamic data operation in RC owing to a combination of rich dynamic and nonlinear electronic properties. The results suggest that SPAN-based electrochemical systems can be applied for material-based computing, by exploiting their intrinsic physicochemical behavior.
Collapse
Affiliation(s)
- Yuki Usami
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 5600043, Japan
- Department of Human Intelligence Systems, Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology (Kyutech), 2-4 Hibikino, Wakamatsu, Kitakyushu, 8080196, Japan
- Research Center for Neuromorphic AI Hardware, Kyushu Institute of Technology (Kyutech), 2-4 Hibikino, Wakamatsu, Kitakyushu, 8080196, Japan
| | - Bram van de Ven
- NanoElectronics Group, MESA+ Institute for Nanotechnology and BRAINS Center for Brain-Inspired Nano Systems, University of Twente, P.O. Box 217, Enschede, 7500 AE, The Netherlands
| | - Dilu G Mathew
- NanoElectronics Group, MESA+ Institute for Nanotechnology and BRAINS Center for Brain-Inspired Nano Systems, University of Twente, P.O. Box 217, Enschede, 7500 AE, The Netherlands
| | - Tao Chen
- NanoElectronics Group, MESA+ Institute for Nanotechnology and BRAINS Center for Brain-Inspired Nano Systems, University of Twente, P.O. Box 217, Enschede, 7500 AE, The Netherlands
| | - Takumi Kotooka
- Department of Human Intelligence Systems, Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology (Kyutech), 2-4 Hibikino, Wakamatsu, Kitakyushu, 8080196, Japan
| | - Yuya Kawashima
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 5600043, Japan
| | - Yuichiro Tanaka
- Department of Human Intelligence Systems, Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology (Kyutech), 2-4 Hibikino, Wakamatsu, Kitakyushu, 8080196, Japan
- Research Center for Neuromorphic AI Hardware, Kyushu Institute of Technology (Kyutech), 2-4 Hibikino, Wakamatsu, Kitakyushu, 8080196, Japan
| | - Yoichi Otsuka
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 5600043, Japan
| | - Hiroshi Ohoyama
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 5600043, Japan
| | - Hakaru Tamukoh
- Department of Human Intelligence Systems, Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology (Kyutech), 2-4 Hibikino, Wakamatsu, Kitakyushu, 8080196, Japan
- Research Center for Neuromorphic AI Hardware, Kyushu Institute of Technology (Kyutech), 2-4 Hibikino, Wakamatsu, Kitakyushu, 8080196, Japan
| | - Hirofumi Tanaka
- Department of Human Intelligence Systems, Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology (Kyutech), 2-4 Hibikino, Wakamatsu, Kitakyushu, 8080196, Japan
- Research Center for Neuromorphic AI Hardware, Kyushu Institute of Technology (Kyutech), 2-4 Hibikino, Wakamatsu, Kitakyushu, 8080196, Japan
| | - Wilfred G van der Wiel
- NanoElectronics Group, MESA+ Institute for Nanotechnology and BRAINS Center for Brain-Inspired Nano Systems, University of Twente, P.O. Box 217, Enschede, 7500 AE, The Netherlands
| | - Takuya Matsumoto
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 5600043, Japan
| |
Collapse
|
4
|
Ruiz Euler HC, Boon MN, Wildeboer JT, van de Ven B, Chen T, Broersma H, Bobbert PA, van der Wiel WG. A deep-learning approach to realizing functionality in nanoelectronic devices. Nat Nanotechnol 2020; 15:992-998. [PMID: 33077963 DOI: 10.1038/s41565-020-00779-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 09/09/2020] [Indexed: 06/11/2023]
Abstract
Many nanoscale devices require precise optimization to function. Tuning them to the desired operation regime becomes increasingly difficult and time-consuming when the number of terminals and couplings grows. Imperfections and device-to-device variations hinder optimization that uses physics-based models. Deep neural networks (DNNs) can model various complex physical phenomena but, so far, are mainly used as predictive tools. Here, we propose a generic deep-learning approach to efficiently optimize complex, multi-terminal nanoelectronic devices for desired functionality. We demonstrate our approach for realizing functionality in a disordered network of dopant atoms in silicon. We model the input-output characteristics of the device with a DNN, and subsequently optimize control parameters in the DNN model through gradient descent to realize various classification tasks. When the corresponding control settings are applied to the physical device, the resulting functionality is as predicted by the DNN model. We expect our approach to contribute to fast, in situ optimization of complex (quantum) nanoelectronic devices.
Collapse
Affiliation(s)
- Hans-Christian Ruiz Euler
- NanoElectronics Group, MESA+ Institute for Nanotechnology, and Center for Brain-Inspired Nano Systems (BRAINS), University of Twente, Enschede, The Netherlands
| | - Marcus N Boon
- NanoElectronics Group, MESA+ Institute for Nanotechnology, and Center for Brain-Inspired Nano Systems (BRAINS), University of Twente, Enschede, The Netherlands
| | - Jochem T Wildeboer
- NanoElectronics Group, MESA+ Institute for Nanotechnology, and Center for Brain-Inspired Nano Systems (BRAINS), University of Twente, Enschede, The Netherlands
| | - Bram van de Ven
- NanoElectronics Group, MESA+ Institute for Nanotechnology, and Center for Brain-Inspired Nano Systems (BRAINS), University of Twente, Enschede, The Netherlands
| | - Tao Chen
- NanoElectronics Group, MESA+ Institute for Nanotechnology, and Center for Brain-Inspired Nano Systems (BRAINS), University of Twente, Enschede, The Netherlands
| | - Hajo Broersma
- Programmable Nanosystems and Formal Methods and Tools, MESA+ Institute for Nanotechnology, DSI Digital Society Institute, and Center for Brain-Inspired Nano Systems (BRAINS), University of Twente, Enschede, The Netherlands
| | - Peter A Bobbert
- NanoElectronics Group, MESA+ Institute for Nanotechnology, and Center for Brain-Inspired Nano Systems (BRAINS), University of Twente, Enschede, The Netherlands
- Molecular Materials and Nanosystems and Center for Computational Energy Research, Department of Applied Physics, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Wilfred G van der Wiel
- NanoElectronics Group, MESA+ Institute for Nanotechnology, and Center for Brain-Inspired Nano Systems (BRAINS), University of Twente, Enschede, The Netherlands.
| |
Collapse
|
5
|
Mathew DG, Beekman P, Lemay SG, Zuilhof H, Le Gac S, van der Wiel WG. Electrochemical Detection of Tumor-Derived Extracellular Vesicles on Nanointerdigitated Electrodes. Nano Lett 2020; 20:820-828. [PMID: 31536360 PMCID: PMC7020140 DOI: 10.1021/acs.nanolett.9b02741] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 09/04/2019] [Indexed: 05/15/2023]
Abstract
Tumor-derived extracellular vesicles (tdEVs) are attracting much attention due to their essential function in intercellular communication and their potential as cancer biomarkers. Although tdEVs are significantly more abundant in blood than other cancer biomarkers, their concentration compared to other blood components remains relatively low. Moreover, the presence of particles in blood with a similar size as that of tdEVs makes their selective and sensitive detection further challenging. Therefore, highly sensitive and specific biosensors are required for unambiguous tdEV detection in complex biological environments, especially for decentralized point-of-care analysis. Here, we report an electrochemical sensing scheme for tdEV detection, with two-level selectivity provided by a sandwich immunoassay and two-level amplification through the combination of an enzymatic assay and redox cycling on nanointerdigitated electrodes to respectively enhance the specificity and sensitivity of the assay. Analysis of prostate cancer cell line tdEV samples at various concentrations revealed an estimated limit of detection for our assay as low as 5 tdEVs/μL, as well as an excellent linear sensor response spreading over 6 orders of magnitude (10-106 tdEVs/μL), which importantly covers the clinically relevant range for tdEV detection in blood. This novel nanosensor and associated sensing scheme opens new opportunities to detect tdEVs at clinically relevant concentrations from a single blood finger prick.
Collapse
Affiliation(s)
- Dilu G. Mathew
- NanoElectronics
Group, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, Enschede, 7500 AE The
Netherlands
| | - Pepijn Beekman
- Laboratory
for Organic Chemistry, Wageningen University, Stippeneng 4, Wageningen, 6708WE The
Netherlands
- Applied
Microfluidics for BioEngineering Research, MESA+ Institute for Nanotechnology,
TechMed Center, University of Twente, P.O. Box 217, Enschede, 7500 AE The Netherlands
| | - Serge G. Lemay
- Bioelectronics,
MESA+ Institute for Nanotechnology, University
of Twente, P.O. Box 217, Enschede, 7500 AE The Netherlands
| | - Han Zuilhof
- Laboratory
for Organic Chemistry, Wageningen University, Stippeneng 4, Wageningen, 6708WE The
Netherlands
- School
of Pharmaceutical Sciences and Technology, Tianjin University, Tianjin, 300072 China
- Department
of Chemical and Materials Engineering, King
Abdulaziz University, Jeddah, 21589 Saudi Arabia
| | - Séverine Le Gac
- Applied
Microfluidics for BioEngineering Research, MESA+ Institute for Nanotechnology,
TechMed Center, University of Twente, P.O. Box 217, Enschede, 7500 AE The Netherlands
| | - Wilfred G. van der Wiel
- NanoElectronics
Group, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, Enschede, 7500 AE The
Netherlands
| |
Collapse
|
6
|
Chen T, van Gelder J, van de Ven B, Amitonov SV, de Wilde B, Ruiz Euler HC, Broersma H, Bobbert PA, Zwanenburg FA, van der Wiel WG. Classification with a disordered dopant-atom network in silicon. Nature 2020; 577:341-345. [PMID: 31942054 DOI: 10.1038/s41586-019-1901-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 11/13/2019] [Indexed: 11/09/2022]
Abstract
Classification is an important task at which both biological and artificial neural networks excel1,2. In machine learning, nonlinear projection into a high-dimensional feature space can make data linearly separable3,4, simplifying the classification of complex features. Such nonlinear projections are computationally expensive in conventional computers. A promising approach is to exploit physical materials systems that perform this nonlinear projection intrinsically, because of their high computational density5, inherent parallelism and energy efficiency6,7. However, existing approaches either rely on the systems' time dynamics, which requires sequential data processing and therefore hinders parallel computation5,6,8, or employ large materials systems that are difficult to scale up7. Here we use a parallel, nanoscale approach inspired by filters in the brain1 and artificial neural networks2 to perform nonlinear classification and feature extraction. We exploit the nonlinearity of hopping conduction9-11 through an electrically tunable network of boron dopant atoms in silicon, reconfiguring the network through artificial evolution to realize different computational functions. We first solve the canonical two-input binary classification problem, realizing all Boolean logic gates12 up to room temperature, demonstrating nonlinear classification with the nanomaterial system. We then evolve our dopant network to realize feature filters2 that can perform four-input binary classification on the Modified National Institute of Standards and Technology handwritten digit database. Implementation of our material-based filters substantially improves the classification accuracy over that of a linear classifier directly applied to the original data13. Our results establish a paradigm of silicon-based electronics for small-footprint and energy-efficient computation14.
Collapse
Affiliation(s)
- Tao Chen
- NanoElectronics Group, MESA+ Institute for Nanotechnology and BRAINS Center for Brain-Inspired Nano Systems, University of Twente, Enschede, The Netherlands
| | - Jeroen van Gelder
- NanoElectronics Group, MESA+ Institute for Nanotechnology and BRAINS Center for Brain-Inspired Nano Systems, University of Twente, Enschede, The Netherlands
| | - Bram van de Ven
- NanoElectronics Group, MESA+ Institute for Nanotechnology and BRAINS Center for Brain-Inspired Nano Systems, University of Twente, Enschede, The Netherlands
| | - Sergey V Amitonov
- NanoElectronics Group, MESA+ Institute for Nanotechnology and BRAINS Center for Brain-Inspired Nano Systems, University of Twente, Enschede, The Netherlands
| | - Bram de Wilde
- NanoElectronics Group, MESA+ Institute for Nanotechnology and BRAINS Center for Brain-Inspired Nano Systems, University of Twente, Enschede, The Netherlands
| | - Hans-Christian Ruiz Euler
- NanoElectronics Group, MESA+ Institute for Nanotechnology and BRAINS Center for Brain-Inspired Nano Systems, University of Twente, Enschede, The Netherlands
| | - Hajo Broersma
- Programmable Nanosystems and Formal Methods and Tools, MESA+ Institute for Nanotechnology, DSI Digital Society Institute and BRAINS Center for Brain-Inspired Nano Systems, University of Twente, Enschede, The Netherlands
| | - Peter A Bobbert
- NanoElectronics Group, MESA+ Institute for Nanotechnology and BRAINS Center for Brain-Inspired Nano Systems, University of Twente, Enschede, The Netherlands.,Molecular Materials and Nanosystems and Center for Computational Energy Research, Department of Applied Physics, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Floris A Zwanenburg
- NanoElectronics Group, MESA+ Institute for Nanotechnology and BRAINS Center for Brain-Inspired Nano Systems, University of Twente, Enschede, The Netherlands
| | - Wilfred G van der Wiel
- NanoElectronics Group, MESA+ Institute for Nanotechnology and BRAINS Center for Brain-Inspired Nano Systems, University of Twente, Enschede, The Netherlands.
| |
Collapse
|
7
|
Yin C, Smink AEM, Leermakers I, Tang LMK, Lebedev N, Zeitler U, van der Wiel WG, Hilgenkamp H, Aarts J. Electron Trapping Mechanism in LaAlO_{3}/SrTiO_{3} Heterostructures. Phys Rev Lett 2020; 124:017702. [PMID: 31976734 DOI: 10.1103/physrevlett.124.017702] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Revised: 09/13/2019] [Indexed: 06/10/2023]
Abstract
In LaAlO_{3}/SrTiO_{3} heterostructures, a still poorly understood phenomenon is that of electron trapping in back-gating experiments. Here, by combining magnetotransport measurements and self-consistent Schrödinger-Poisson calculations, we obtain an empirical relation between the amount of trapped electrons and the gate voltage. The amount of trapped electrons decays exponentially away from the interface. However, contrary to earlier observations, we find that the Fermi level remains well within the quantum well. The enhanced trapping of electrons induced by the gate voltage can therefore not be explained by a thermal escape mechanism. Further gate sweeping experiments strengthen that conclusion. We propose a new mechanism which involves the electromigration and clustering of oxygen vacancies in SrTiO_{3} and argue that such electron trapping is a universal phenomenon in SrTiO_{3}-based two-dimensional electron systems.
Collapse
Affiliation(s)
- Chunhai Yin
- Huygens-Kamerlingh Onnes Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands
| | - Alexander E M Smink
- MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Inge Leermakers
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - Lucas M K Tang
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - Nikita Lebedev
- Huygens-Kamerlingh Onnes Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands
| | - Uli Zeitler
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - Wilfred G van der Wiel
- MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Hans Hilgenkamp
- MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Jan Aarts
- Huygens-Kamerlingh Onnes Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands
| |
Collapse
|
8
|
Ridderbos J, Brauns M, de Vries FK, Shen J, Li A, Kölling S, Verheijen MA, Brinkman A, van der Wiel WG, Bakkers EPAM, Zwanenburg FA. Hard Superconducting Gap and Diffusion-Induced Superconductors in Ge-Si Nanowires. Nano Lett 2020; 20:122-130. [PMID: 31771328 PMCID: PMC6953474 DOI: 10.1021/acs.nanolett.9b03438] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 11/19/2019] [Indexed: 05/28/2023]
Abstract
We show a hard superconducting gap in a Ge-Si nanowire Josephson transistor up to in-plane magnetic fields of 250 mT, an important step toward creating and detecting Majorana zero modes in this system. A hard gap requires a highly homogeneous tunneling heterointerface between the superconducting contacts and the semiconducting nanowire. This is realized by annealing devices at 180 °C during which aluminum interdiffuses and replaces the germanium in a section of the nanowire. Next to Al, we find a superconductor with lower critical temperature (TC = 0.9 K) and a higher critical field (BC = 0.9-1.2 T). We can therefore selectively switch either superconductor to the normal state by tuning the temperature and the magnetic field and observe that the additional superconductor induces a proximity supercurrent in the semiconducting part of the nanowire even when the Al is in the normal state. In another device where the diffusion of Al rendered the nanowire completely metallic, a superconductor with a much higher critical temperature (TC = 2.9 K) and critical field (BC = 3.4 T) is found. The small size of these diffusion-induced superconductors inside nanowires may be of special interest for applications requiring high magnetic fields in arbitrary direction.
Collapse
Affiliation(s)
- Joost Ridderbos
- MESA
+ Institute for Nanotechnology, University
of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Matthias Brauns
- QuTech
and Kavli Institute of Nanoscience, Delft
University of Technology, 2600 GA Delft, The Netherlands
| | - Folkert K. de Vries
- MESA
+ Institute for Nanotechnology, University
of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Jie Shen
- QuTech
and Kavli Institute of Nanoscience, Delft
University of Technology, 2600 GA Delft, The Netherlands
| | - Ang Li
- Department
of Applied Physics, Eindhoven University
of Technology, Postbox 513, 5600 MB Eindhoven, The Netherlands
| | - Sebastian Kölling
- Department
of Applied Physics, Eindhoven University
of Technology, Postbox 513, 5600 MB Eindhoven, The Netherlands
| | - Marcel A. Verheijen
- Department
of Applied Physics, Eindhoven University
of Technology, Postbox 513, 5600 MB Eindhoven, The Netherlands
| | - Alexander Brinkman
- MESA
+ Institute for Nanotechnology, University
of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Wilfred G. van der Wiel
- MESA
+ Institute for Nanotechnology, University
of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Erik P. A. M. Bakkers
- Department
of Applied Physics, Eindhoven University
of Technology, Postbox 513, 5600 MB Eindhoven, The Netherlands
| | - Floris A. Zwanenburg
- MESA
+ Institute for Nanotechnology, University
of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| |
Collapse
|
9
|
Spruijtenburg PC, Amitonov SV, Wiel WGVD, Zwanenburg FA. A fabrication guide for planar silicon quantum dot heterostructures. Nanotechnology 2018; 29:143001. [PMID: 29384491 DOI: 10.1088/1361-6528/aaabf5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We describe important considerations to create top-down fabricated planar quantum dots in silicon, often not discussed in detail in literature. The subtle interplay between intrinsic material properties, interfaces and fabrication processes plays a crucial role in the formation of electrostatically defined quantum dots. Processes such as oxidation, physical vapor deposition and atomic-layer deposition must be tailored in order to prevent unwanted side effects such as defects, disorder and dewetting. In two directly related manuscripts written in parallel we use techniques described in this work to create depletion-mode quantum dots in intrinsic silicon, and low-disorder silicon quantum dots defined with palladium gates. While we discuss three different planar gate structures, the general principles also apply to 0D and 1D systems, such as self-assembled islands and nanowires.
Collapse
Affiliation(s)
- Paul C Spruijtenburg
- NanoElectronics Group, MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
| | | | | | | |
Collapse
|
10
|
Makarenko KS, Liu Z, de Jong MP, Zwanenburg FA, Huskens J, van der Wiel WG. Bottom-Up Single-Electron Transistors. Adv Mater 2017; 29:1702920. [PMID: 28922482 DOI: 10.1002/adma.201702920] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 08/02/2017] [Indexed: 06/07/2023]
Abstract
As the downscaling of conventional semiconductor electronics becomes more and more challenging, the interest in alternative material systems and fabrication methods is growing. A novel bottom-up approach for the fabrication of high-quality single-electron transistors (SETs) that can easily be contacted electrically in a controllable manner is developed. This approach employs the self-assembly of Au nanoparticles forming the SETs, and Au nanorods forming the leads to macroscopic electrodes, thus bridging the gap between the nano- and microscale. Low-temperature electron-transport measurements reveal exemplary single-electron tunneling characteristics. SET behavior can be significantly changed, post-fabrication, using molecular exchange of the tunnel barriers, demonstrating the tunability of the assemblies. These results form a promising proof of principle for the versatility of bottom-up nanoelectronics, and toward controlled fabrication of nanoelectronic devices.
Collapse
Affiliation(s)
- Ksenia S Makarenko
- NanoElectronics Group MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500, AE, Enschede, The Netherlands
| | - Zhihua Liu
- NanoElectronics Group MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500, AE, Enschede, The Netherlands
| | - Michel P de Jong
- NanoElectronics Group MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500, AE, Enschede, The Netherlands
| | - Floris A Zwanenburg
- NanoElectronics Group MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500, AE, Enschede, The Netherlands
| | - Jurriaan Huskens
- Molecular NanoFabrication Group, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500, AE, Enschede, The Netherlands
| | - Wilfred G van der Wiel
- NanoElectronics Group MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500, AE, Enschede, The Netherlands
| |
Collapse
|
11
|
Ye L, González-Campo A, Kudernac T, Núñez R, de Jong M, van der Wiel WG, Huskens J. Monolayer Contact Doping from a Silicon Oxide Source Substrate. Langmuir 2017; 33:3635-3638. [PMID: 28351137 PMCID: PMC5397885 DOI: 10.1021/acs.langmuir.7b00157] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 03/21/2017] [Indexed: 06/06/2023]
Abstract
Monolayer contact doping (MLCD) is a modification of the monolayer doping (MLD) technique that involves monolayer formation of a dopant-containing adsorbate on a source substrate. This source substrate is subsequently brought into contact with the target substrate, upon which the dopant is driven into the target substrate by thermal annealing. Here, we report a modified MLCD process, in which we replace the commonly used Si source substrate by a thermally oxidized substrate with a 100 nm thick silicon oxide layer, functionalized with a monolayer of a dopant-containing silane. The thermal oxide potentially provides a better capping effect and effectively prevents the dopants from diffusing back into the source substrate. The use of easily accessible and processable silane monolayers provides access to a general and modifiable process for the introduction of dopants on the source substrate. As a proof of concept, a boron-rich carboranyl-alkoxysilane was used here to construct the monolayer that delivers the dopant, to boost the doping level in the target substrate. X-ray photoelectron spectroscopy (XPS) showed a successful grafting of the dopant adsorbate onto the SiO2 surface. The achieved doping levels after thermal annealing were similar to the doping levels acessible by MLD as demonstrated by secondary ion mass spectrometry measurements. The method shows good prospects, e.g. for use in the doping of Si nanostructures.
Collapse
Affiliation(s)
- Liang Ye
- Molecular
NanoFabrication and NanoElectronics groups, MESA+ Institute for
Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Arántzazu González-Campo
- Functional Nanomaterials and Surfaces and Inorganic Materials and Catalysis
groups, Institut de Ciència de Materials
de Barcelona (ICMAB-CSIC), Campus de la UAB, 08193, Bellaterra, Spain
| | - Tibor Kudernac
- Molecular
NanoFabrication and NanoElectronics groups, MESA+ Institute for
Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Rosario Núñez
- Functional Nanomaterials and Surfaces and Inorganic Materials and Catalysis
groups, Institut de Ciència de Materials
de Barcelona (ICMAB-CSIC), Campus de la UAB, 08193, Bellaterra, Spain
| | - Michel de Jong
- Molecular
NanoFabrication and NanoElectronics groups, MESA+ Institute for
Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Wilfred G. van der Wiel
- Molecular
NanoFabrication and NanoElectronics groups, MESA+ Institute for
Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Jurriaan Huskens
- Molecular
NanoFabrication and NanoElectronics groups, MESA+ Institute for
Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| |
Collapse
|
12
|
Veerbeek J, Ye L, Vijselaar W, Kudernac T, van der Wiel WG, Huskens J. Highly doped silicon nanowires by monolayer doping. Nanoscale 2017; 9:2836-2844. [PMID: 28169380 DOI: 10.1039/c6nr07623h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Controlling the doping concentration of silicon nanostructures is challenging. Here, we investigated three different monolayer doping techniques to obtain silicon nanowires with a high doping dose. These routes were based on conventional monolayer doping, starting from covalently bound dopant-containing molecules, or on monolayer contact doping, in which a source substrate coated with a monolayer of a carborane silane was the dopant source. As a third route, both techniques were combined to retain the benefits of conformal monolayer formation and the use of an external capping layer. These routes were used for doping fragile porous nanowires fabricated by metal-assisted chemical etching. Differences in porosity were used to tune the total doping dose inside the nanowires, as measured by X-ray photoelectron spectroscopy and secondary ion mass spectrometry measurements. The higher the porosity, the higher was the surface available for dopant-containing molecules, which in turn led to a higher doping dose. Slightly porous nanowires could be doped via all three routes, which resulted in highly doped nanowires with (projected areal) doping doses of 1014-1015 boron atoms per cm2 compared to 1012 atoms per cm2 for a non-porous planar sample. Highly porous nanowires were not compatible with the conventional monolayer doping technique, but monolayer contact doping and the combined route resulted for these highly porous nanowires in tremendously high doping doses up to 1017 boron atoms per cm2.
Collapse
Affiliation(s)
- Janneke Veerbeek
- Molecular NanoFabrication, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
| | - Liang Ye
- Molecular NanoFabrication, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands. and NanoElectronics group, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Wouter Vijselaar
- Molecular NanoFabrication, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
| | - Tibor Kudernac
- Molecular NanoFabrication, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
| | - Wilfred G van der Wiel
- NanoElectronics group, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Jurriaan Huskens
- Molecular NanoFabrication, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
| |
Collapse
|
13
|
Wang K, Strambini E, Sanderink JGM, Bolhuis T, van der Wiel WG, de Jong MP. Effect of Orbital Hybridization on Spin-Polarized Tunneling across Co/C 60 Interfaces. ACS Appl Mater Interfaces 2016; 8:28349-28356. [PMID: 27624282 DOI: 10.1021/acsami.6b08313] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The interaction between ferromagnetic surfaces and organic semiconductors leads to the formation of hybrid interfacial states. As a consequence, the local magnetic moment is altered, a hybrid interfacial density of states (DOS) is formed, and spin-dependent shifts of energy levels occur. Here, we show that this hybridization affects spin transport across the interface significantly. We report spin-dependent electronic transport measurements for tunnel junctions comprising C60 molecular thin films grown on top of face-centered-cubic (fcc) epitaxial Co electrodes, an AlOx tunnel barrier, and an Al counter electrode. Since only one ferromagnetic electrode (Co) is present, spin-polarized transport is due to tunneling anisotropic magnetoresistance (TAMR). An in-plane TAMR ratio of approximately 0.7% has been measured at 5 K under application of a magnetic field of 800 mT. The magnetic switching behavior shows some remarkable features, which are attributed to the rotation of interfacial magnetic moments. This behavior can be ascribed to the magnetic coupling between the Co thin films and the newly formed Co/C60 hybridized interfacial states. Using the Tedrow-Meservey technique, the tunnel spin polarization of the Co/C60 interface was found to be 43%.
Collapse
Affiliation(s)
- Kai Wang
- NanoElectronics (NE) Group, MESA+ Institute for Nanotechnology, University of Twente , P. O. Box 217, Enschede 7500AE, The Netherlands
| | - Elia Strambini
- NanoElectronics (NE) Group, MESA+ Institute for Nanotechnology, University of Twente , P. O. Box 217, Enschede 7500AE, The Netherlands
| | - Johnny G M Sanderink
- NanoElectronics (NE) Group, MESA+ Institute for Nanotechnology, University of Twente , P. O. Box 217, Enschede 7500AE, The Netherlands
| | - Thijs Bolhuis
- NanoElectronics (NE) Group, MESA+ Institute for Nanotechnology, University of Twente , P. O. Box 217, Enschede 7500AE, The Netherlands
| | - Wilfred G van der Wiel
- NanoElectronics (NE) Group, MESA+ Institute for Nanotechnology, University of Twente , P. O. Box 217, Enschede 7500AE, The Netherlands
| | - Michel P de Jong
- NanoElectronics (NE) Group, MESA+ Institute for Nanotechnology, University of Twente , P. O. Box 217, Enschede 7500AE, The Netherlands
| |
Collapse
|
14
|
Mueller F, Schouten RN, Brauns M, Gang T, Lim WH, Lai NS, Dzurak AS, van der Wiel WG, Zwanenburg FA. Erratum: "Printed circuit board metal powder filters for low electron temperatures" [Rev. Sci. Instrum. 84, 044706 (2013)]. Rev Sci Instrum 2016; 87:079903. [PMID: 27475615 DOI: 10.1063/1.4959151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Affiliation(s)
- Filipp Mueller
- NanoElectronics Group, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, Enschede, AE 7500, The Netherlands
| | - Raymond N Schouten
- Kavli Institute of Nanoscience, Delft University of Technology, Delft, GA 2600, The Netherlands
| | - Matthias Brauns
- NanoElectronics Group, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, Enschede, AE 7500, The Netherlands
| | - Tian Gang
- NanoElectronics Group, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, Enschede, AE 7500, The Netherlands
| | - Wee Han Lim
- ARC Centre of Excellence for Quantum Computation and Communication Technology, The University of New South Wales, Sydney 2052, Australia
| | - Nai Shyan Lai
- ARC Centre of Excellence for Quantum Computation and Communication Technology, The University of New South Wales, Sydney 2052, Australia
| | - Andrew S Dzurak
- ARC Centre of Excellence for Quantum Computation and Communication Technology, The University of New South Wales, Sydney 2052, Australia
| | - Wilfred G van der Wiel
- NanoElectronics Group, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, Enschede, AE 7500, The Netherlands
| | - Floris A Zwanenburg
- NanoElectronics Group, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, Enschede, AE 7500, The Netherlands
| |
Collapse
|
15
|
Ye L, González-Campo A, Núñez R, de Jong MP, Kudernac T, van der Wiel WG, Huskens J. Boosting the Boron Dopant Level in Monolayer Doping by Carboranes. ACS Appl Mater Interfaces 2015; 7:27357-61. [PMID: 26595856 DOI: 10.1021/acsami.5b08952] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Monolayer doping (MLD) presents an alternative method to achieve silicon doping without causing crystal damage, and it has the capability of ultrashallow doping and the doping of nonplanar surfaces. MLD utilizes dopant-containing alkene molecules that form a monolayer on the silicon surface using the well-established hydrosilylation process. Here, we demonstrate that MLD can be extended to high doping levels by designing alkenes with a high content of dopant atoms. Concretely, carborane derivatives, which have 10 B atoms per molecule, were functionalized with an alkene group. MLD using a monolayer of such a derivative yielded up to ten times higher doping levels, as measured by X-ray photoelectron spectroscopy and dynamic secondary mass spectroscopy, compared to an alkene with a single B atom. Sheet resistance measurements showed comparably increased conductivities of the Si substrates. Thermal budget analyses indicate that the doping level can be further optimized by changing the annealing conditions.
Collapse
Affiliation(s)
- Liang Ye
- Molecular NanoFabrication group and ‡NanoElectronics Group, MESA+ Institute for Nanotechnology, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands
- Functional Nanomaterials and Surfaces group and ∥Inorganic Materials and Catalysis group, Institut de Ciència de Materials de Barcelona (ICMAB-CSIC) , Campus de la UAB, 08193, Bellaterra, Spain
| | - Arántzazu González-Campo
- Molecular NanoFabrication group and ‡NanoElectronics Group, MESA+ Institute for Nanotechnology, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands
- Functional Nanomaterials and Surfaces group and ∥Inorganic Materials and Catalysis group, Institut de Ciència de Materials de Barcelona (ICMAB-CSIC) , Campus de la UAB, 08193, Bellaterra, Spain
| | - Rosario Núñez
- Molecular NanoFabrication group and ‡NanoElectronics Group, MESA+ Institute for Nanotechnology, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands
- Functional Nanomaterials and Surfaces group and ∥Inorganic Materials and Catalysis group, Institut de Ciència de Materials de Barcelona (ICMAB-CSIC) , Campus de la UAB, 08193, Bellaterra, Spain
| | - Michel P de Jong
- Molecular NanoFabrication group and ‡NanoElectronics Group, MESA+ Institute for Nanotechnology, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands
- Functional Nanomaterials and Surfaces group and ∥Inorganic Materials and Catalysis group, Institut de Ciència de Materials de Barcelona (ICMAB-CSIC) , Campus de la UAB, 08193, Bellaterra, Spain
| | - Tibor Kudernac
- Molecular NanoFabrication group and ‡NanoElectronics Group, MESA+ Institute for Nanotechnology, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands
- Functional Nanomaterials and Surfaces group and ∥Inorganic Materials and Catalysis group, Institut de Ciència de Materials de Barcelona (ICMAB-CSIC) , Campus de la UAB, 08193, Bellaterra, Spain
| | - Wilfred G van der Wiel
- Molecular NanoFabrication group and ‡NanoElectronics Group, MESA+ Institute for Nanotechnology, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands
- Functional Nanomaterials and Surfaces group and ∥Inorganic Materials and Catalysis group, Institut de Ciència de Materials de Barcelona (ICMAB-CSIC) , Campus de la UAB, 08193, Bellaterra, Spain
| | - Jurriaan Huskens
- Molecular NanoFabrication group and ‡NanoElectronics Group, MESA+ Institute for Nanotechnology, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands
- Functional Nanomaterials and Surfaces group and ∥Inorganic Materials and Catalysis group, Institut de Ciència de Materials de Barcelona (ICMAB-CSIC) , Campus de la UAB, 08193, Bellaterra, Spain
| |
Collapse
|
16
|
Mueller F, Konstantaras G, Spruijtenburg PC, van der Wiel WG, Zwanenburg FA. Electron-Hole Confinement Symmetry in Silicon Quantum Dots. Nano Lett 2015; 15:5336-5341. [PMID: 26134900 DOI: 10.1021/acs.nanolett.5b01706] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We report electrical transport measurements on a gate-defined ambipolar quantum dot in intrinsic silicon. The ambipolarity allows its operation as either an electron or a hole quantum dot of which we change the dot occupancy by 20 charge carriers in each regime. Electron-hole confinement symmetry is evidenced by the extracted gate capacitances and charging energies. The results demonstrate that ambipolar quantum dots offer great potential for spin-based quantum information processing, since confined electrons and holes can be compared and manipulated in the same crystalline environment.
Collapse
Affiliation(s)
- Filipp Mueller
- NanoElectronics Group, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Georgios Konstantaras
- NanoElectronics Group, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Paul C Spruijtenburg
- NanoElectronics Group, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Wilfred G van der Wiel
- NanoElectronics Group, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Floris A Zwanenburg
- NanoElectronics Group, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| |
Collapse
|
17
|
Ye L, Pujari SP, Zuilhof H, Kudernac T, de Jong MP, van der Wiel WG, Huskens J. Controlling the dopant dose in silicon by mixed-monolayer doping. ACS Appl Mater Interfaces 2015; 7:3231-6. [PMID: 25607722 DOI: 10.1021/am5079368] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Molecular monolayer doping (MLD) presents an alternative to achieve doping of silicon in a nondestructive way and holds potential for realizing ultrashallow junctions and doping of nonplanar surfaces. Here, we report the mixing of dopant-containing alkenes with alkenes that lack this functionality at various ratios to control the dopant concentration in the resulting monolayer and concomitantly the dopant dose in the silicon substrate. The mixed monolayers were grafted onto hydrogen-terminated silicon using well-established hydrosilylation chemistry. Contact angle measurements, X-ray photon spectroscopy (XPS) on the boron-containing monolayers, and Auger electron spectroscopy on the phosphorus-containing monolayers show clear trends as a function of the dopant-containing alkene concentration. Dynamic secondary-ion mass spectroscopy (D-SIMS) and Van der Pauw resistance measurements on the in-diffused samples show an effective tuning of the doping concentration in silicon.
Collapse
Affiliation(s)
- Liang Ye
- Molecular NanoFabrication group, MESA+ Institute for Nanotechnology and ‡NanoElectronics Group, MESA+ Institute for Nanotechnology, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands
| | | | | | | | | | | | | |
Collapse
|
18
|
Zoontjes MGC, Huijben M, Baltrusaitis J, van der Wiel WG, Mul G. Selective hydrothermal method to create patterned and photoelectrochemically effective Pt/WO3 interfaces. ACS Appl Mater Interfaces 2013; 5:13050-13054. [PMID: 24256114 DOI: 10.1021/am4039536] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
A hydrothermal method based on the use of hydrogen peroxide is described to grow a homogeneous layer of tungsten oxide (WO3) on a platinum (Pt) film supported on a silicon wafer. WO3 growth is highly selective for Pt when present on silicon in a patterned arrangement, demonstrating that Pt catalyzes decomposition of the WO3 precursor in solution. The obtained Pt/WO3 interface yields high photocurrents of 1.1 mA/cm(2) in photoelectrochemical water splitting when illuminated by a solar simulator. The photocurrents are significantly higher than most previously reported values for hydrothermally grown layers on indium-tin oxide and fluorine-tin oxide glasses. The selective growth method thus provides new options to effectively implement WO3 in photoelectrochemical devices.
Collapse
Affiliation(s)
- Michel G C Zoontjes
- MESA+ Institute for Nanotechnology, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands
| | | | | | | | | |
Collapse
|
19
|
Mueller F, Schouten RN, Brauns M, Gang T, Lim WH, Lai NS, Dzurak AS, van der Wiel WG, Zwanenburg FA. Printed circuit board metal powder filters for low electron temperatures. Rev Sci Instrum 2013; 84:044706. [PMID: 23635219 DOI: 10.1063/1.4802875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We report the characterisation of printed circuit boards (PCB) metal powder filters and their influence on the effective electron temperature which is as low as 22 mK for a quantum dot in a silicon MOSFET structure in a dilution refrigerator. We investigate the attenuation behaviour (10 MHz-20 GHz) of filter made of four metal powders with a grain size below 50 μm. The room-temperature attenuation of a stainless steel powder filter is more than 80 dB at frequencies above 1.5 GHz. In all metal powder filters, the attenuation increases with temperature. Compared to classical powder filters, the design presented here is much less laborious to fabricate and specifically the copper powder PCB-filters deliver an equal or even better performance than their classical counterparts.
Collapse
Affiliation(s)
- Filipp Mueller
- NanoElectronics Group, MESA+ Institute for Nanotechnology, University of Twente, Enschede, The Netherlands.
| | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Rianasari I, de Jong MP, Huskens J, van der Wiel WG. Covalent Coupling of Nanoparticles with Low-Density Functional Ligands to Surfaces via Click Chemistry. Int J Mol Sci 2013; 14:3705-17. [PMID: 23434666 PMCID: PMC3588066 DOI: 10.3390/ijms14023705] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 02/02/2013] [Accepted: 02/05/2013] [Indexed: 11/16/2022] Open
Abstract
We demonstrate the application of the 1,3-dipolar cycloaddition (“click” reaction) to couple gold nanoparticles (Au NPs) functionalized with low densities of functional ligands. The ligand coverage on the citrate-stabilized Au NPs was adjusted by the ligand:Au surface atom ratio, while maintaining the colloidal stability of the Au NPs in aqueous solution. A procedure was developed to determine the driving forces governing the selectivity and reactivity of citrate-stabilized and ligand-functionalized Au NPs on patterned self-assembled monolayers. We observed selective and remarkably stable chemical bonding of the Au NPs to the complimentarily functionalized substrate areas, even when estimating that only 1–2 chemical bonds are formed between the particles and the substrate.
Collapse
Affiliation(s)
| | | | - Jurriaan Huskens
- Authors to whom correspondence should be addressed; E-Mails: (J.H.); (W.G.W.); Tel.: +31-53-489-2995 (J.H.); +31-53-489-2873 (W.G.W.); Fax: +31-53-489-4645 (J.H.); +31-53-489-4571 (W.G.W.)
| | - Wilfred G. van der Wiel
- Authors to whom correspondence should be addressed; E-Mails: (J.H.); (W.G.W.); Tel.: +31-53-489-2995 (J.H.); +31-53-489-2873 (W.G.W.); Fax: +31-53-489-4645 (J.H.); +31-53-489-4571 (W.G.W.)
| |
Collapse
|
21
|
Tran TLA, Cakır D, Wong PKJ, Preobrajenski AB, Brocks G, van der Wiel WG, de Jong MP. Magnetic properties of bcc-Fe(001)/C₆₀ interfaces for organic spintronics. ACS Appl Mater Interfaces 2013; 5:837-841. [PMID: 23305202 DOI: 10.1021/am3024367] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The magnetic structure of the interfaces between organic semiconductors and ferromagnetic contacts plays a key role in the spin injection and extraction processes in organic spintronic devices. We present a combined computational (density functional theory) and experimental (X-ray magnetic circular dichroism) study on the magnetic properties of interfaces between bcc-Fe(001) and C(60) molecules. C(60) is an interesting candidate for application in organic spintronics due to the absence of hydrogen atoms and the associated hyperfine fields. Adsorption of C(60) on Fe(001) reduces the magnetic moments on the top Fe layers by ∼6%, while inducing an antiparrallel magnetic moment of ∼-0.2 μ(B) on C(60). Adsorption of C(60) on a model ferromagnetic substrate consisting of three Fe monolayers on W(001) leads to a different structure but to very similar interface magnetic properties.
Collapse
Affiliation(s)
- T Lan Anh Tran
- NanoElectronics Group, MESA+ Institute for Nanotechnology, University of Twente , PO Box 217, 7500 AE Enschede, The Netherlands
| | | | | | | | | | | | | |
Collapse
|
22
|
Voorthuijzen WP, Yilmaz MD, Naber WJM, Huskens J, van der Wiel WG. Local doping of silicon using nanoimprint lithography and molecular monolayers. Adv Mater 2011; 23:1346-50. [PMID: 21400594 DOI: 10.1002/adma.201003625] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2010] [Revised: 11/12/2010] [Indexed: 05/15/2023]
Affiliation(s)
- W Pim Voorthuijzen
- Molecular Nanofabrication Group, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | | | | | | | | |
Collapse
|
23
|
Abstract
Controlled assembly of ferromagnetic nanoparticles on surfaces is of crucial importance for a range of spintronic and data storage applications. Here, we present a novel method for assembling monolayers of ferromagnetic FePt nanoparticles on silicon oxide substrates using "click chemistry". Reaction of alkyne-functionalized FePt nanoparticles with azide-terminated self-assembled monolayers (SAMs), on silicon oxide, leads to the irreversible attachment of magnetic nanoparticles to the surface via triazole linkers. Based on this covalent interaction, well-packed monolayers of FePt nanoparticles were prepared and nanoparticle patterns are generated on surfaces via microcontact printing (μCP).
Collapse
Affiliation(s)
- Sachin Kinge
- Laboratory of Supramolecular Chemistry and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
| | | | | | | | | |
Collapse
|
24
|
Voorthuijzen WP, Yilmaz MD, Gomez-Casado A, Jonkheijm P, van der Wiel WG, Huskens J. Direct patterning of covalent organic monolayers on silicon using nanoimprint lithography. Langmuir 2010; 26:14210-14215. [PMID: 20695632 DOI: 10.1021/la101445n] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Two fabrication schemes are reported for the direct patterning of organic monolayers on oxide-free silicon, combining top-down nanoimprint lithography and bottom-up monolayer formation. The first approach was designed to form monolayer patterns on the imprinted areas, while the second approach was designed for monolayer formation outside of the imprinted features. By both approaches, covalently bonded Si-C monolayer patterns with feature sizes ranging from 100 nm to 100 microm were created via a hydrosilylation procedure using diluted reagents. Both unfunctionalized and omega-functionalized alkenes were patterned successfully.
Collapse
Affiliation(s)
- W Pim Voorthuijzen
- Molecular Nanofabrication group, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | | | | | | | | | | |
Collapse
|
25
|
Yildirim O, Gang T, Kinge S, Reinhoudt DN, Blank DH, van der Wiel WG, Rijnders G, Huskens J. Monolayer-directed assembly and magnetic properties of FePt nanoparticles on patterned aluminum oxide. Int J Mol Sci 2010; 11:1162-79. [PMID: 20480007 PMCID: PMC2869229 DOI: 10.3390/iijms11031162] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Accepted: 03/03/2010] [Indexed: 11/23/2022] Open
Abstract
FePt nanoparticles (NPs) were assembled on aluminum oxide substrates, and their ferromagnetic properties were studied before and after thermal annealing. For the first time, phosph(on)ates were used as an adsorbate to form self-assembled monolayers (SAMs) on alumina to direct the assembly of NPs onto the surface. The Al2O3 substrates were functionalized with aminobutylphosphonic acid (ABP) or phosphonoundecanoic acid (PNDA) SAMs or with poly(ethyleneimine) (PEI) as a reference. FePt NPs assembled on all of these monolayers, but much less on unmodified Al2O3, which shows that ligand exchange at the NPs is the most likely mechanism of attachment. Proper modification of the Al2O3 surface and controlling the immersion time of the modified Al2O3 substrates into the FePt NP solution resulted in FePt NPs assembly with controlled NP density. Alumina substrates were patterned by microcontact printing using aminobutylphosphonic acid as the ink, allowing local NP assembly. Thermal annealing under reducing conditions (96%N2/4%H2) led to a phase change of the FePt NPs from the disordered FCC phase to the ordered FCT phase. This resulted in ferromagnetic behavior at room temperature. Such a process can potentially be applied in the fabrication of spintronic devices.
Collapse
Affiliation(s)
- Oktay Yildirim
- Molecular Nanofabrication Group, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands
- Inorganic Materials Science, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands
| | - Tian Gang
- NanoElectronics Group, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands
| | - Sachin Kinge
- NanoElectronics Group, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands
- Supramolecular Chemistry & Technology, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands
| | - David N. Reinhoudt
- Molecular Nanofabrication Group, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands
- Supramolecular Chemistry & Technology, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands
| | - Dave H.A. Blank
- Inorganic Materials Science, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands
| | - Wilfred G. van der Wiel
- NanoElectronics Group, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands
- Authors to whom correspondence should be addressed; E-Mails:
(W.G.W.);
(G. R.);
(J.H.); Tel.: +31-53-4892873 (W.G.W.); +31-53-4892618 (G.R.); +31-53-4892995 (J.H.); Fax: +31-53-4893343 (W.G.W.); +31-53-4893595 (G.R.); +31-53-4894645 (J.H.)
| | - Guus Rijnders
- Inorganic Materials Science, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands
- Authors to whom correspondence should be addressed; E-Mails:
(W.G.W.);
(G. R.);
(J.H.); Tel.: +31-53-4892873 (W.G.W.); +31-53-4892618 (G.R.); +31-53-4892995 (J.H.); Fax: +31-53-4893343 (W.G.W.); +31-53-4893595 (G.R.); +31-53-4894645 (J.H.)
| | - Jurriaan Huskens
- Molecular Nanofabrication Group, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands
- Authors to whom correspondence should be addressed; E-Mails:
(W.G.W.);
(G. R.);
(J.H.); Tel.: +31-53-4892873 (W.G.W.); +31-53-4892618 (G.R.); +31-53-4892995 (J.H.); Fax: +31-53-4893343 (W.G.W.); +31-53-4893595 (G.R.); +31-53-4894645 (J.H.)
| |
Collapse
|
26
|
Chen S, Bomer JG, van der Wiel WG, Carlen ET, van den Berg A. Top-down fabrication of sub-30 nm monocrystalline silicon nanowires using conventional microfabrication. ACS Nano 2009; 3:3485-3492. [PMID: 19856905 DOI: 10.1021/nn901220g] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We report a new low-cost top-down silicon nanowire fabrication technology requiring only conventional microfabrication processes including microlithography, oxidation, and wet anisotropic plane-dependent etching; high quality silicon nanowire arrays can be easily made in any conventional microfabrication facility without nanolithography or expensive equipment. Silicon nanowires with scalable lateral dimensions ranging from 200 nm down to 10-20 nm and lengths up to approximately 100 microm can be precisely formed with near-perfect monocrystalline cross sections, atomically smooth surfaces, and wafer-scale yields greater than 90% using a novel size reduction method where silicon nanowires can be controllably scaled to any dimension and doping concentration independent of large contacting regions from a continuous layer of crystalline silicon.
Collapse
Affiliation(s)
- Songyue Chen
- BIOS Lab on a Chip Group, University of Twente, Enschede, The Netherlands
| | | | | | | | | |
Collapse
|
27
|
Kinge S, Gang T, Naber WJM, Boschker H, Rijnders G, Reinhoudt DN, van der Wiel WG. Low-temperature solution synthesis of chemically functional ferromagnetic FePtAu nanoparticles. Nano Lett 2009; 9:3220-3224. [PMID: 19691342 DOI: 10.1021/nl901465s] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Magnetic nanoparticles are of great scientific and technological interest. The application of ferromagnetic nanoparticles for high-density data storage has great potential, but energy efficient synthesis of uniform, isolated, and patternable nanoparticles that remain ferromagnetic at room temperature is not trivial. Here, we present a low-temperature solution synthesis method for FePtAu nanoparticles that addresses all those issues and therefore can be regarded as an important step toward applications. We show that the onset of the chemically ordered face-centered tetragonal (L1(0)) phase is obtained for thermal annealing temperatures as low as 150 degrees C. Large uniaxial magnetic anisotropy (10(7) erg/cm(3)) and a high long-range order parameter have been obtained. Our low-temperature solution annealing leaves the organic ligands intact, so that the possibility for postanneal monolayer formation and chemically assisted patterning on a surface is maintained.
Collapse
Affiliation(s)
- Sachin Kinge
- Strategic Research Orientation NanoElectronics, Laboratory of Supramolecular Chemistry and Technology, Faculty of Science and Technology, and Inorganic Materials Science Group, Faculty of Science and Technology, MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands.
| | | | | | | | | | | | | |
Collapse
|
28
|
Tong HD, Chen S, van der Wiel WG, Carlen ET, van den Berg A. Novel top-down wafer-scale fabrication of single crystal silicon nanowires. Nano Lett 2009; 9:1015-1022. [PMID: 19199755 DOI: 10.1021/nl803181x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A new low-cost, top-down nanowire fabrication technology is presented not requiring nanolithography and suitable for any conventional microtechnology cleanroom facility. This novel wafer-scale process technology uses a combination of angled thin-film deposition and etching of a metal layer in a precisely defined cavity with a single micrometer-scale photolithography step. Electrically functional silicon and metallic nanowires with lengths up to several millimeters, lateral widths of 100 nm, and thicknesses 20 nm have been realized and tested. Device characterization includes a general description of device operation, electrochemical biasing, and sensitivity for sensor applications followed by electrical measurements showing linear i-v characteristics with specific contact resistivity rhoc approximately 4 x 10-4 ohm's cm2 and electrochemical behavior of the oxidized silicon nanowires is described with the site-binding model.
Collapse
Affiliation(s)
- Hien Duy Tong
- BIOS Lab on a Chip Group, Strategic Research Orientation NanoElectronics, University of Twente, Enschede, The Netherlands.
| | | | | | | | | |
Collapse
|
29
|
Tokura Y, van der Wiel WG, Obata T, Tarucha S. Coherent single electron spin control in a slanting Zeeman field. Phys Rev Lett 2006; 96:047202. [PMID: 16486882 DOI: 10.1103/physrevlett.96.047202] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2005] [Indexed: 05/06/2023]
Abstract
We consider a single electron in a 1D quantum dot with a static slanting Zeeman field. By combining the spin and orbital degrees of freedom of the electron, an effective quantum two-level (qubit) system is defined. This pseudospin can be coherently manipulated by the voltage applied to the gate electrodes, without the need for an external time-dependent magnetic field or spin-orbit coupling. Single-qubit rotations and the controlled-NOT operation can be realized. We estimated the relaxation (T1) and coherence (T2) times and the (tunable) quality factor. This scheme implies important experimental advantages for single electron spin control.
Collapse
Affiliation(s)
- Yasuhiro Tokura
- NTT Basic Research Laboratories, NTT Corporation, Atsugi-shi, Kanagawa 243-0198, Japan
| | | | | | | |
Collapse
|