A5089760121- Advancements in Semiconductor Devices and Circuit Design
- Semiconductor materials and devices
- Quantum and electron transport phenomena
- Nanowire Synthesis and Applications
- Graphene research and applications
- Integrated Circuits and Semiconductor Failure Analysis
- Topological Materials and Phenomena
- Molecular Junctions and Nanostructures
- Photonic and Optical Devices
- Semiconductor materials and interfaces
- Carbon Nanotubes in Composites
- Physics of Superconductivity and Magnetism
- Semiconductor Quantum Structures and Devices
- Advanced Memory and Neural Computing
- Electronic and Structural Properties of Oxides
- Quantum Computing Algorithms and Architecture
- Electron and X-Ray Spectroscopy Techniques
- Advancements in Battery Materials
- Ferroelectric and Negative Capacitance Devices
- Graphene and Nanomaterials Applications
- Mechanical and Optical Resonators
- Surface and Thin Film Phenomena
- Carbon and Quantum Dots Applications
- Silicon Carbide Semiconductor Technologies
- Neuroscience and Neural Engineering
Forschungszentrum Jülich
2016-2025
Stadtwerke Jülich (Germany)
2020
Jülich Aachen Research Alliance
2009-2017
Harvard University Press
2014
Cornell University
2014
University of California, Berkeley
2014
University of Notre Dame
2014
University of Kaiserslautern
2006-2009
Ernst Ruska Centre
2003
Small spin-qubit registers defined by single electrons confined in Si/SiGe quantum dots operate successfully and connecting these would permit scalable computation. Shuttling the qubit carrying between is a natural choice for high-fidelity coherent links provided overhead of control signals stays moderate. Our proof-of-principle demonstrates shuttling electron propagating wave-potential an electrostatically 420 nm long quantum-channel. This conveyor-mode approach requires independent from...
The connectivity within single carrier information-processing devices requires transport and storage of charge quanta. Single electrons have been adiabatically transported while confined to a moving quantum dot in short, all-electrical Si/SiGe shuttle device, called bus (QuBus). Here we show QuBus spanning length 10 μm operated by only six simply-tunable voltage pulses. We introduce characterization method, shuttle-tomography, benchmark the potential imperfections local shuttle-fidelity...
Inverters based on uniaxially tensile strained Si (sSi) nanowire (NW) tunneling field-effect transistors (TFETs) are fabricated. Tilted dopant implantation using the gate as a shadow mask allows self-aligned formation of p-i-n TFETs. The steep junctions formed by segregation at low temperatures improve band-to-band tunneling, resulting in higher on-currents n- and p-TFETs > 10 μA/μm <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> <sub...
Guided by the Wentzel-Kramers–Brillouin approximation for band-to-band tunneling (BTBT), various performance boosters Si TFETs are presented and experimentally verified. Along this line, improvements achieved implementation of uniaxial strain in nanowires (NW), benefits high-k/metal gates, newly engineered junctions as well effect scaling NW to diameters 10 nm demonstrated. Specifically, self-aligned ion implantation into source/drain silicide dopant segregation has been exploited achieve...
In this letter, we systematically investigate the impact of gate length and channel orientation on electrical performance tunneling field-effect transistors (TFETs). We fabricate characterize Si/SiGe heterostructure TFETs with p-doped compressively strained Si <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5</sub> Ge source, intrinsic channel, n-doped drain. observe a linear relation length, L...
Electron and hole Bloch states in gapped bilayer graphene exhibit topological orbital magnetic moments with opposite signs near the band edges, which allows for tunable valley-polarization an out-of-plane field. This intrinsic property makes electron quantum dots (QDs) interesting valley spin-valley qubits. Here we show measurements of electron-hole crossover a QD, demonstrating sign associated Berry curvature. Using three layers metallic top gates, independently control tunneling barriers...
Understanding how the electron spin is coupled to orbital degrees of freedom, such as a valley degree freedom in solid-state systems central applications spin-based electronics and quantum computation. Recent developments preparation electrostatically-confined dots gapped bilayer graphene (BLG) enables study low-energy single-electron spectra BLG dots, which crucial for potential spin-valley qubit operations. Here, we present observation coupling dot regime. By making use highly-tunable...
The integration of semiconductor Josephson junctions (JJs) in superconducting quantum circuits provides a versatile platform for hybrid qubits and offers powerful way to probe exotic quasiparticle excitations. Recent proposals using circuit electrodynamics (cQED) detect topological superconductivity motivate the novel materials such circuits. Here, we report on realization transmon implemented with (Bi0.06Sb0.94)2Te3 insulator (TI) JJs ultrahigh vacuum fabrication techniques. Microwave...
We present gate all around strained Si (sSi) nanowire array TFETs with high I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ON</sub> (64μA/μm at V xmlns:xlink="http://www.w3.org/1999/xlink">DD</sub> =1.0V). Pulsed I-V measurements provide small SS and record xmlns:xlink="http://www.w3.org/1999/xlink">60</sub> of 1×10 <sup xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> μA/μm 300K due to the suppression trap assisted tunneling (TAT)....
This paper presents a novel SiGe/Si tunneling field-effect transistor (TFET) which exploits line parallel with the gate electric field. The device makes use of selective and self-adjusted silicidation counter doped pocket within SiGe layer at source tunnel junction, resulting in high on-current Ion = 6.7 μA/μm supply voltage VDD −0.5 V constant subthreshold swing (SS) about 80 mV/dec over four orders magnitude drain-current Id.
In this letter, we present complementary tunneling field-effect transistors (CTFETs) based on strained Si with gate all around nanowire structures a single chip. The main focus is to suppress the ambipolar behavior of TFETs gate-drain underlap. Detailed device characterization and demonstration CTFET inverter show that current successfully eliminated for both pand n-devices. transfer characteristics indicate maximum separation high/low level sharp transition (high voltage gain) at Vdd down...
We report on finite bias spectroscopy measurements of the two-electron spectrum in a gate defined bilayer graphene (BLG) quantum dot for varying magnetic fields. The spin and valley degree freedom BLG give rise to multiplets six orbital symmetric ten antisymmetric states. find that states are lower energy separated by ≈ 0.4-0.8 meV from multiplet exhibits an additional splitting its 0.15-0.5 due lattice scale interactions. experimental observations supported theoretical calculations, which...
Twisted bilayer graphene (tBLG) near the magic angle is a unique platform where combination of topology and strong correlations gives rise to exotic electronic phases. These phases are gate-tunable related presence flat bands, isolated by single-particle band gaps. This enables gate-controlled charge confinements, essential for operation single-electron transistors (SETs), allows one explore interplay confinement, electron interactions, renormalization, moiré superlattice, potentially...
This letter presents experimental results on tunneling field-effect transistors featuring arrays of Ω-gated uniaxially strained and unstrained silicon nanowires. The gate control a SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /poly-Si stack is compared with high- <i xmlns:xlink="http://www.w3.org/1999/xlink">k</i> /metal stack. Steep inverse subthreshold slopes down to 76 mV/dec relatively high on-currents were achieved the...
The reliable fabrication of nanoelectrode pairs with predefined separations in the few nanometer range is an essential prerequisite for future nanoelectronic devices. Here we demonstrate a fine-tuned electron-beam lithographic (EBL) route which suitable defining gap size down to 3 ± 1 nm and yield 55%. This achievement based on optimized two-layer resist system combination adopted developer system, as well elaborated pattern design taking into consideration EBL inherent proximity effect....
We report tunneling spectroscopy experiments on a bilayer graphene double quantum dot device that can be tuned by all-graphene lateral gates. The diameter of the two dots are around 50 nm and constrictions acting as barriers 30 in width. features addition energies order 20 meV. Charge stability diagrams allow us to study tunable interdot coupling energy well spectrum electronic excited states number individual triple points over large range. obtained constant level spacing 1.75 meV wide...
A half SRAM cell with strained Si nanowire complementary tunnel-FETs (TFETs) was fabricated and characterized to explore the feasibility functionality of 6T-SRAM based on TFETs. Outward-faced n-TFETs are used as access-transistors. Static measurements were performed determine butterfly curves, allowing assessment stability. The forward p-i-n leakage access-transistor at certain bias configurations leads malfunctioning storage operation, even without contribution ambipolar behavior. At large...
We report on the investigation of periodic superstructures in twisted bilayer graphene (tBLG) van-der-Waals heterostructures, where one layers is aligned to hexagonal boron nitride (hBN). Our theoretical simulations reveal that if ratio resulting two moir\'e unit cell areas a simple fraction, graphene/hBN lattice acts as staggered potential, breaking degeneracy between tBLG AA sites. This leads additional band gaps at energies subset sites fully occupied. These manifest Landau fans...
Confinement in topological insulator nanoribbon Josephson junctions leads to a gapped electron-hole bound state spectrum.
Graphene and bilayer graphene quantum dots are promising hosts for spin qubits with long coherence times. Although recent technological improvements make it possible to confine single electrons electrostatically in their valley texture of the single-particle spectrum has been studied detail, relaxation dynamics remains still unexplored. Here, we report on transport through a high-frequency gate-controlled single-electron dot. By transient current spectroscopy states, extract lower bound time...
We present electron transport measurements on lithographically defined and etched graphene nanoconstrictions with different aspect ratios including lengths (l) widths (w). A roughly length-independent disorder induced effective energy gap can be observed around the charge neutrality point. This scales inversely width even in regimes where length of constriction is smaller than its (l&lt;w). In very short constrictions, we observe both resonances due to localized states or charged islands...