A5059570588- Quantum and electron transport phenomena
- Advancements in Semiconductor Devices and Circuit Design
- Semiconductor materials and devices
- Semiconductor Quantum Structures and Devices
- Nanowire Synthesis and Applications
- Topological Materials and Phenomena
- Physics of Superconductivity and Magnetism
- Surface and Thin Film Phenomena
- Semiconductor materials and interfaces
- Molecular Junctions and Nanostructures
- Force Microscopy Techniques and Applications
- Advanced Electron Microscopy Techniques and Applications
- Electron and X-Ray Spectroscopy Techniques
- Diamond and Carbon-based Materials Research
- Advanced Thermoelectric Materials and Devices
- Microwave Engineering and Waveguides
- Semiconductor Lasers and Optical Devices
- Electrostatic Discharge in Electronics
- Graphene research and applications
- Machine Learning in Materials Science
- Mechanical and Optical Resonators
- Silicon Nanostructures and Photoluminescence
- Advanced Memory and Neural Computing
- Aerogels and thermal insulation
- Quantum Information and Cryptography
University of Twente
2015-2025
Delft University of Technology
2007-2016
Eindhoven University of Technology
2016
QuTech
2016
UNSW Sydney
2009-2013
Centre for Quantum Computation and Communication Technology
2009-2013
Aalto University
2013
Asia Pacific University of Technology & Innovation
2013
Australian Research Council
2010
Philips (Netherlands)
2007
This review describes recent groundbreaking results in Si, $\mathrm{Si}/\mathrm{SiGe}$, and dopant-based quantum dots, it highlights the remarkable advances Si-based physics that have occurred past few years. progress has been possible thanks to materials development of Si devices, physical understanding effects silicon. Recent critical steps include isolation single electrons, observation spin blockade, single-shot readout individual electron spins both dopants gated dots Si. Each these...
The authors use double quantum dot transport measurements to reveal the presence of a strong spin-orbit interaction in Ge/Si nanowires. They also show that this gives rise g-factor renormalization with magnetic field.
Double quantum dots are convenient solid-state platforms to encode information. Two-electron spin states can be conveniently detected and manipulated using strong selection rules based on the Pauli exclusion principle, leading well-know blockade of electron transport for triplet states. Coherent would optimally preserved in an environment free nuclear spins, which is achievable silicon by isotopic purification. Here we report a deliberately engineered, gate-defined metal-oxide-semiconductor...
We report on low-temperature electronic transport measurements of a silicon metal-oxide-semiconductor quantum dot, with independent gate control electron densities in the leads and dot island. This architecture allows energy levels to be probed without affecting density leads, vice versa. Appropriate biasing enables occupancy reduced single-electron level, as evidenced by magnetospectroscopy ground state first two charge transitions. Independent reservoirs also discrimination between excited...
We show how a scanning probe microscope (SPM) can be used to image electron flow through InAs nanowires, elucidating the physics of nanowire devices on local scale. A charged SPM tip is as movable gate. Images conductance versus position spatially map nanowires at liquid-He temperatures. Plots backgate voltage without present complex patterns Coulomb-blockade peaks. identify their source multiple quantum dots formed by disorder along nanowireeach dot surrounded series concentric rings...
We report measurements on a silicon nanowire quantum dot with clarity that allows for complete understanding of the spin states first four holes. First, we show control hole number down to one. Detailed at perpendicular magnetic fields reveal Zeeman splitting single in silicon. are able determine ground-state configuration one holes occupying and find filling alternating spin-down spin-up holes, which is confirmed by magnetospectroscopy up 9T. Additionally, so far inexplicable feature...
The ability of core–shell nanowires to overcome existing limitations heterostructures is one the key ingredients for design next generation devices. This requires a detailed understanding mechanism strain relaxation in these systems order eliminate strain-induced defect formation and thus boost important electronic properties such as carrier mobility. Here we demonstrate how hole mobility [110]-oriented Ge–Si can be substantially enhanced thanks realization large band offset coherent system,...
We present angle-dependent measurements of the effective g-factor g* in a Ge-Si core-shell nanowire quantum dot. is found to be maximum when magnetic field pointing perpendicular both and electric induced by local gates. Alignment with reduces significantly. almost completely quenched aligned axis. These findings confirm recent calculations, where obtained anisotropy attributed Rashba-type spin-orbit interaction heavy-hole light-hole mixing. In principle, this facilitates manipulation qubits...
We present a systematic review of features due to resonant electron tunnelling, observable in transport spectroscopy experiments on quantum dots and single donors. The covers attributable intrinsic properties the dot (orbital, spin valley states) as well extrinsic effects (phonon/photon emission/absorption, charge reservoirs, coupling nearby centres). focus most common operating conditions, neglecting strong leads. By discussing experimental signatures each type feature, we aim at providing...
We report charge sensing measurements of a silicon metal-oxide-semiconductor quantum dot using single-electron transistor as sensor with dynamic feedback control. Using digitally-controlled feedback, the exhibits sensitive and robust detection state dot, even in presence drifts random upset events. The enables occupancy to be probed down single electron level.
We present measurements on gate-defined double quantum dots in Ge-Si core-shell nanowires, which we tune to a regime with visible shell filling both dots. observe Pauli spin blockade and can assign the measured leakage current at low magnetic fields spin-flip cotunneling, for measure strong anisotropy related an anisotropic $g$ factor. At higher see signatures caused by spin-orbit coupling between (1,1) singlet (2,0) triplet states. Taking into account these mechanisms, choose field...
We report the demonstration of a low-disorder silicon metal–oxide–semiconductor (Si MOS) quantum dot containing tunable number electrons from zero to N = 27. The observed evolution addition energies with parallel magnetic field reveals spin filling into valley–orbit states. find splitting 0.10 meV between ground and first excited states, consistent theory placing lower bound on valley splitting. Our results provide optimism for realisation in near future qubits based dots.
We report the characterisation of printed circuit boards (PCB) metal powder filters and their influence on effective electron temperature which is as low 22 mK for a quantum dot in silicon MOSFET structure dilution refrigerator. investigate attenuation behaviour (10 MHz- 20 GHz) filter made four powders with grain size below 50 um. The room-temperature stainless steel more than 80 dB at frequencies above 1.5 GHz. In all increases temperature. Compared to classical filters, design presented...
We present a Josephson junction based on Ge-Si core-shell nanowire with transparent superconducting Al contacts, building block which could be of considerable interest for investigating Majorana bound states, qubits, and Andreev (spin) qubits. demonstrate the dc effect in form finite supercurrent through establish ac by showing up to 23 Shapiro steps. observe multiple reflections sixth order, indicating that charges can scatter elastically many times inside our interfaces between...
Abstract A variety of quantum transport experiments are reported in SnTe nanowire devices. Research on these particular devices is relevant because their topological properties and potential to distinguish surface states owing high surface‐to‐volume ratio that suppresses the bulk contribution conductance. low‐resistance a high‐resistance regime observed. The highly resistive display semiconducting dot behavior caused by microscopic differences fabrication, while with low resistance show...
In this letter we report single-hole tunneling through a quantum dot in two-dimensional hole gas, situated narrow-channel field-effect transistor intrinsic silicon. Two layers of aluminum gate electrodes are defined on Si/SiO2 using electron-beam lithography. Fabrication and subsequent electrical characterization different devices yield reproducible results, such as typical MOSFET turn-on pinch-off characteristics. Additionally, linear transport measurements at 4 K result regularly spaced...
We replace the established aluminium gates for formation of quantum dots in silicon with made from palladium. study morphology both and palladium transmission electron microscopy. The native oxide is found to be formed all around gates, which could lead unintentional dots. Therefore, we report on a novel fabrication route that replaces its by atomic-layer-deposition-grown oxide. Using this approach, show low-disorder gate-defined dots, are reproducibly fabricated. Furthermore, enables us...
Low dimensional semiconducting structures with strong spin-orbit interaction (SOI) and induced superconductivity attracted much interest in the search for topological superconductors. Both SOI hard superconducting gap are directly related to protection of predicted Majorana bound states. Here we explore one-dimensional hole gas germanium silicon (Ge-Si) core-shell nanowires (NWs) as a new material candidate creating superconductor. Fitting multiple Andreev reflection measurements shows that...
We present an automated protocol for tuning single-electron transistors (SETs) or single-hole (SHTs) to operate as precise charge sensors. Using minimal device-specific information, the performs measurements enable selection and ranking of high-sensitivity operating points. It also characterizes key device parameters, such dot radius gate lever arms, through acquisition analysis Coulomb diamonds. Demonstration on accumulation-mode silicon SET at 1.5 K highlights its potential in 1-2 range...