A5067914826- Semiconductor materials and devices
- GaN-based semiconductor devices and materials
- Quantum and electron transport phenomena
- Semiconductor materials and interfaces
- Quantum Information and Cryptography
- Plasma Diagnostics and Applications
- Integrated Circuits and Semiconductor Failure Analysis
- Metal and Thin Film Mechanics
- Advancements in Semiconductor Devices and Circuit Design
- Atomic and Subatomic Physics Research
- Semiconductor Quantum Structures and Devices
- Quantum Computing Algorithms and Architecture
- Copper Interconnects and Reliability
- Physics of Superconductivity and Magnetism
- Semiconductor Lasers and Optical Devices
- Mechanical and Optical Resonators
- ZnO doping and properties
- Microwave Engineering and Waveguides
- Cold Atom Physics and Bose-Einstein Condensates
- Electromagnetic Compatibility and Measurements
- Quantum optics and atomic interactions
- Radio Wave Propagation Studies
- Photonic and Optical Devices
- Electronic Packaging and Soldering Technologies
- Metallurgical and Alloy Processes
Karlsruhe Institute of Technology
2014-2024
Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Gran Sasso
2022
National Institute for Research and Development of Isotopic and Molecular Technologies
2022
Istituto Nazionale di Fisica Nucleare, Sezione di Roma I
2022
Maxwell Sensors
2011
Pioneer (United States)
2011
Sandia National Laboratories California
1993-2002
Sandia National Laboratories
1993-1999
AT&T (United States)
1996
University of Florida
1996
Abstract Approaches to developing large-scale superconducting quantum processors must cope with the numerous microscopic degrees of freedom that are ubiquitous in solid-state devices. State-of-the-art qubits employ aluminium oxide (AlO x ) tunnel Josephson junctions as sources nonlinearity necessary perform operations. Analyses these typically assume an idealized, purely sinusoidal current–phase relation. However, this relation is expected hold only limit vanishingly low-transparency...
Inductively coupled plasma (ICP) etch rates for GaN are reported as a function of pressure, chemistry, rf power, and ICP power. Using Cl2/H2/Ar high 6875 Å/min reported. The surface morphology remains smooth over wide range conditions quantified using atomic force microscopy. Several yield highly anisotropic profiles with sidewalls. These results have direct application to the fabrication group-III nitride etched laser facets.
Resonator measurements are a simple but powerful tool to characterize material's microwave response. The losses of resonant mode quantified by its internal quality factor ${Q}_{\mathrm{i}}$, which can be extracted from the scattering coefficient in reflection or transmission measurement. Here we show that systematic error on ${Q}_{\mathrm{i}}$ arises Fano interference signal with background path. Limited knowledge interfering paths given setup translates into range uncertainty for increases...
Inductively coupled plasma (ICP) etching of GaAs, GaP, and InP is reported as a function chemistry, chamber pressure, rf power, source power. Etches were characterized in terms rate anisotropy using scanning electron microscopy, root-mean-square surface roughness atomic force microscopy. ICP etch rates compared to cyclotron resonance for Cl2/Ar, Cl2/N2, BCl3/Ar, BCl3/N2 plasmas under similar conditions. High GaAs GaP (exceeding 1500 nm/min) obtained Cl2-based due the high concentration...
Determining the state of a qubit on time scale much shorter than its relaxation is an essential requirement for quantum information processing. With aid nondegenerate parametric amplifier, we demonstrate continuous detection jumps transmon with $90\mathrm{%}$ fidelity discrimination. Entirely fabricated by standard two-step optical-lithography techniques, this type amplifier consists dispersion-engineered Josephson-junction (JJ) array. By using long arrays, containing...
Reading out the state of superconducting artificial atoms typically relies on dispersive coupling to a readout resonator. For given system noise temperature, increasing circulating photon number $\bar{n}$ in resonator enables shorter measurement time and is therefore expected reduce errors caused by spontaneous atom transitions. However, generally observed also increase these transition rates. Here we present fluxonium which measure an overall flat dependence rates between its first two...
Reactively sputtered AlN is shown by electrical characterization of Pt/Au Schottky diodes to be an effect encapsulant for GaN annealed at 1100 °C. formed on encapsulated with during the anneal had low reverse leakage currents breakdown voltages in excess 40 V. In contrast, samples without layer 3–4 orders-of-magnitude higher currents. Atomic force microscopy images as-grown and also demonstrate increase surface roughness a change morphology uncapped following annealing. Auger electron...
We present cavity QED experiments with an ${\mathrm{Er}}^{3+}:{\mathrm{Y}}_{2}\phantom{\rule{0.16em}{0ex}}{\mathrm{SiO}}_{5}$ crystal magnetically coupled to a three-dimensional (3D) cylindrical sapphire loaded copper resonator. Such waveguide cavities are promising for the realization of superconducting quantum processor. Here, we demonstrate coherent integration rare-earth spin ensemble 3D architecture. The collective coupling strength ${\mathrm{Er}}^{3+}$ spins is 21 MHz. resonator...
Superconducting qubits equipped with quantum non-demolishing readout and active feedback can be used as information engines to probe manipulate microscopic degrees of freedom, whether intentionally designed or naturally occurring in their environment. In the case spin systems, required magnetic field bias presents a challenge for superconductors Josephson junctions. Here we demonstrate granular aluminum nanojunction fluxonium qubit (gralmonium) spectrum coherence resilient fields beyond one...
In contrast to the commonly used qubit resonator transverse coupling via $\sigma_{xy}$-degree of freedom, longitudinal through $\sigma_z$ presents a tantalizing alternative: it does not hybridize modes, eliminating Purcell decay, and enables quantum-non-demolishing readout independent qubit-resonator frequency detuning. Here, we demonstrate between {Cr$_7$Ni} molecular spin ensemble kinetic inductance granular aluminum superconducting microwave resonator. The inherent frequency-independence...
Si + implant activation efficiencies above 90%, even at doses of 5×1015 cm−2, have been achieved in GaN by rapid thermal processing 1400–1500 °C for 10 s. The annealing system utilizes molybdenum intermetallic heating elements capable operation up to 1900 °C, producing high and cooling rates (up 100 s−1). Unencapsulated shows severe surface pitting 1300 complete loss the film evaporation 1400 °C. Dissociation nitrogen from is found occur with an approximate energy 3.8 eV (compared 4.4 AlN...
Quantum memories are integral parts of both quantum computers and communication networks. Naturally, such a memory is embedded into hybrid architecture, which has to meet the requirements fast gates, long coherence times, distance communication. Erbium-doped crystals well suited as microwave for superconducting circuits with additional access optical telecom $C$ band around 1.55 $\ensuremath{\mu}\mathrm{m}$. Here, we report on circuit QED experiments an...
We demonstrate a qubit-readout architecture where the dispersive coupling is entirely mediated by kinetic inductance. This allows us to engineer shift of readout resonator independent qubit and capacitances. validate pure concept various generalized flux regimes from plasmon fluxon, with shifts ranging 60 kHz 2 MHz at half-flux quantum sweet spot. achieve performances comparable conventional architectures state preparation fidelities 99.7% 92.7% for ground excited states, respectively, below...
We demonstrate flux-bias locking and operation of a gradiometric fluxonium artificial atom using two symmetric granular aluminum (grAl) loops to implement the superinductor. The shows orders magnitude suppression sensitivity homogeneous magnetic fields, which can be an asset for hybrid quantum systems requiring strong field biasing. By cooling down device in external while crossing metal-to-superconductor transition, locked either at $0$ or $\Phi_0/2$ effective flux bias, corresponding even...
Plasma-induced etch damage often degrades the electrical and optical performance of III–V high-density integrated circuits photonic devices. We have investigated etch-induced electron cyclotron resonance (ECR) generated plasmas on mesa-isolated GaAs pn-junction diodes. Cl2/Ar, BCl3/Ar, Cl2/BCl3/Ar, SiCl4/Ar ECR at ion energies ranging from 10 to 200 eV were studied. Diodes fabricated under low dc-bias (≤100 V) conditions yielded reverse-bias currents which comparable wet-chemical-etched As...
The high kinetic inductance offered by granular aluminum (grAl) has recently been employed for linear inductors in superconducting high-impedance qubits and detectors. Due to its large critical current density compared typical Josephson junctions, resilience external magnetic fields, low dissipation, grAl may also provide a robust source of non-linearity strongly driven quantum circuits, topological superconductivity, hybrid systems. Having said that, can the be sufficient build qubit? Here...
Josephson junction parametric amplifiers have become essential tools for microwave quantum circuit readout with minimal added noise. Even after improving at an impressive rate in the past decade, they remain vulnerable to magnetic fields, which limits their use many applications such as spin qubits, Andreev and molecular magnet devices, dark matter searches, etc. Kinetic inductance materials, granular aluminum (grAl), offer alternative source of nonlinearity innate field resilience. We...
Fast discrimination between quantum states of superconducting artificial atoms is an important ingredient for information processing. In circuit electrodynamics, increasing the signal-field amplitude in readout resonator, dispersively coupled to atom, improves signal-to-noise ratio and increases measurement strength. Here, we employ this effect over 2 orders magnitude power, made possible by unique combination a dimer-Josephson-junction-array amplifier with large dynamic range fact that our...
High rate etching of through-substrate via holes are essential to many GaAs electronic and photonic device applications. The backside relevant monolithic microwave integrated circuits for low inductance grounding increased circuit complexity. Via have also become important devices such as transmission modulators vertical cavity surface emitting lasers (VCSELs) fabricated on absorbing substrates. We investigated compared reactive ion etch (RIE) electron cyclotron resonance (ECR) results...
A variety of different possible donor and acceptor impurities have been implanted into GaN annealed up to 1450 °C. S+ Te+ produce peak electron concentrations ⩽5×1018 cm−3, well below that achievable with Si+. Mg produces p-type conductivity, but Be+- C+- samples remained n type. No redistribution was observed for any the species °C annealing. Much more effective damage removal achieved 1400 annealing high-dose (5×1015 cm−2) Si+ GaN, compared commonly used 1100
High kinetic inductance materials constitute a valuable resource for superconducting quantum circuits and hybrid architectures. Superconducting granular aluminum (grAl) reaches sheet inductances in the nH/$\square$ range, with proven applicability bits microwave detectors. Here we show that single photon internal quality factor $Q_{\mathrm{i}}$ of grAl resonators exceeds $10^5$ magnetic fields up to 1T, aligned in-plane films. Small perpendicular fields, range 0.5mT, enhance by approximately...
The effect of plasma-induced damage on the majority carrier transport properties p-type GaAs has been studied by monitoring changes in sheet resistance (Rs) thin conducting layers under various plasma conditions including etch for refractory metal contacts. Rs determined from transmission line measurements are used to evaluate electron cyclotron resonance (ECR) and reactive ion (RIE) varying thickness doping epitaxial layers. Damage depths calculated data show a strong dependence levels....