A5064418468- Diamond and Carbon-based Materials Research
- Electronic and Structural Properties of Oxides
- Semiconductor materials and devices
- Metal and Thin Film Mechanics
- Advanced Surface Polishing Techniques
- Mercury impact and mitigation studies
- Electrochemical Analysis and Applications
- Physics of Superconductivity and Magnetism
- High-pressure geophysics and materials
- Quantum and electron transport phenomena
- Analytical chemistry methods development
- Particle Detector Development and Performance
- Analytical Chemistry and Sensors
- Advancements in Semiconductor Devices and Circuit Design
Princeton University
2025
London Centre for Nanotechnology
2016-2023
University College London
2016-2023
The lifetime of superconducting qubits is limited by dielectric loss, and a major source loss the native oxide present at surface metal. Specifically, tantalum-based have been demonstrated with record lifetimes, but presence two-level systems in tantalum oxide. Here, we demonstrate strategy for avoiding formation encapsulating noble metals that do not form By depositing few nanometers Au or AuPd alloy before breaking vacuum, completely suppress formation. Microwave measurements resonators...
Diamond is desired for active semiconducting device because of it high carrier mobility, voltage breakdown resistance, and thermal diffusivity. Exploiting diamond as a semiconductor hampered by the lack shallow dopants to create sufficient electronic carriers at room temperature. In this work, nanometer thick, heavily boron doped epitaxial ‘delta doped’ layers have been grown on ultra smooth surfaces which demonstrate p type conduction with enhanced Hall mobilities up 120 cm 2 /Vs sheet...
Low defect smooth substrates are essential to achieve high quality diamond epitaxial growth and performance devices. The optimization of the Ar/O2/CF4 reactive ion etching (RIE) plasma treatment for substrate smoothing its effectiveness remove subsurface polishing damage characterized. An O2/CF4 RIE process effect different parameters (inductively coupled plasma, platen power, pressure) were initially examined. This process, however, still produced a detrimental surface roughness, with etch...
Abstract To exploit the exceptional properties of diamond, new high quality fabrication techniques are needed to produce performing devices. Etching and patterning diamond depths beyond one micron has proven challenging due hardness chemical resistance diamond. A cyclic Ar/O 2 - Ar/Cl ICP RIE process been developed address micromasking issues from aluminium mask by optimising proportion O in plasma introducing a preferential “cleaning” step. High smooth features up to, but not limited 10.6 μ...
Abstract This work compares the electrochemical windows of polished and unpolished boron doped diamond (BDD) electrodes with hydrogen oxygen terminations at a series temperatures up to 125 °C. The experiment was run 5 bar pressure avoid complications due bubble formation. An alternative method for determining window is compared most commonly used method, which defines an arbitrary current density cut-off (J ) value. heavily influenced by mass transport electrolyte cannot be compare across...
Abstract This work compares the electrochemical impedance response of polished and unpolished boron doped diamond (BDD) electrodes, during mercury detection measurements. For each substrate type both bare electrodes decorated with average diameter 30 nm AuNPs were used, to investigate role sensing electrodes. In square wave anodic stripping voltammetry (SWASV) measurements for detection, ions in electrolyte are deposited onto, then stripped from electrode surface. To different performances...
The lifetime of superconducting qubits is limited by dielectric loss, and a major source loss the native oxide present at surface metal. Specifically, tantalum-based have been demonstrated with record lifetimes, but presence two-level systems (TLSs) in tantalum oxide. Here, we demonstrate strategy for avoiding formation encapsulating noble metals that do not form By depositing few nanometers Au or AuPd alloy before breaking vacuum, completely suppress formation. Microwave measurements...
Surface transfer-doping, involving hydrogen terminated diamond surfaces, has been an effective method for producing devices some years but suffered from poor device longevity and reproducibility. The emergence of metal oxides as encapsulant begun to change this situation. Here, HfO2 encapsulated surface transfer doped Schottky diodes with stable characteristics have demonstrated. Ideality factor barrier heights the did not vary considerably across extended periods use (up 39 days). showed...
Abstract This work compares polished and unpolished boron doped diamond (BDD) electrodes decorated with two sizes of gold nanoparticles (AuNPs) for use as robust mercury sensors in aquatic environments. The size the catalytically active AuNPs on electrode surfaces was demonstrated to have a less significant effect sensitivity detection than surface preparation BDD. lowest limits were achieved BDD electrodes, which both detected at concentration 1 pM, six orders magnitude greater limit 5 μM...
Diamond is used as detector material in high energy physics experiments due to its inherent radiation tolerance. The RD42 collaboration has measured the tolerance of chemical vapour deposition (CVD) diamond against proton, pion, and neutron irradiation. Results this study are summarized article. detectors can be further enhanced by using a 3D electrode geometry. We present preliminary results poly-crystalline CVD (pCVD) with geometry after irradiation compare planar devices roughly same thickness.
Carrier confinement in nanowire (NW) structures can offer a host of new material properties compared to bulk electronic devices. Diamond be considered an ultimate semiconductor given its superlative electronic, physical, and optical properties. However, the development diamond device technology has been hindered by doping problems conventional structures. Here, heavily doped NWs, some 15 nm wide only 1–2 deep overcome these issues significant advance NW technology; transistor action induced...