A5059936005- Diamond and Carbon-based Materials Research
- Semiconductor materials and devices
- Electronic and Structural Properties of Oxides
- Quantum and electron transport phenomena
- Integrated Circuits and Semiconductor Failure Analysis
- Force Microscopy Techniques and Applications
- Advancements in Semiconductor Devices and Circuit Design
- Graphene research and applications
- Quantum, superfluid, helium dynamics
- High-pressure geophysics and materials
- Physics of Superconductivity and Magnetism
- Cold Atom Physics and Bose-Einstein Condensates
- Ion-surface interactions and analysis
- Quantum Computing Algorithms and Architecture
- Electron and X-Ray Spectroscopy Techniques
- Molecular Junctions and Nanostructures
- Atomic and Subatomic Physics Research
- Metal and Thin Film Mechanics
- Organic Electronics and Photovoltaics
- Fullerene Chemistry and Applications
- Quantum Information and Cryptography
- Surface and Thin Film Phenomena
- Spectroscopy and Quantum Chemical Studies
- Semiconductor materials and interfaces
- Advanced Materials Characterization Techniques
La Trobe University
2016-2025
Physical Sciences (United States)
2024-2025
Xiamen University
2013
Quanzhou Normal University
2013
Centre for Quantum Computation and Communication Technology
2001-2007
The University of Melbourne
2001-2007
Quantum (Australia)
2001-2003
The University of Queensland
2003
National Physical Laboratory
2000-2002
University of Birmingham
1995-2000
We demonstrate a method for the controlled implantation of single ions into silicon substrate with energy sub-20-keV. The is based on collection electron-hole pairs generated in by impact ion. have used to implant 14-keV P31 through nanoscale masks as route fabrication devices donors silicon.
Fast and reliable DNA sequencing is a long-standing target in biomedical research. Recent advances graphene-based electrical sensors have demonstrated their unprecedented sensitivity to adsorbed molecules, which holds great promise for label-free technology. To date, the proposed approaches rely on ability of graphene electric devices probe molecular-specific interactions with surface. Here we experimentally demonstrate use field-effect transistors (GFETs) as probes presence layer individual...
Abstract Many advanced applications of diamond materials are now being limited by unknown surface defects, including in the fields high power/frequency electronics and quantum computing sensing. Of acute interest to researchers worldwide is loss coherence near‐surface nitrogen‐vacancy (NV) centers generation associated magnetic noise at surface. Here for first time presented observation a family primal which suggested as leading cause band‐bending Fermi‐pinning phenomena devices. A...
Abstract Recently, Greiner et al. [ Nat. Mater. 2012, 11 , 76 ] published a survey of the level alignment about 40 metal oxide/organic molecule interfaces. They observed striking regularity in electronic highest occupied molecular orbital (HOMO) and Fermi that depends solely on difference between substrate work function ionization energy independent details structure oxide. The authors could reproduce their data under assumption thermodynamic equilibrium occupation HOMO using four adjustable...
Abstract Control over the quantum states of individual luminescent nitrogen‐vacancy (NV) centres in nanodiamonds (NDs) is demonstrated by careful design crystal host: its size, surface functional groups, and interfacing substrate. By progressive etching ND host, NV are induced to switch from latent, through continuous, intermittent or “blinking” emission states. The blinking mechanism centre NDs elucidated a qualitative model proposed explain this phenomenon terms electron(s) tunnelling...
The work function and electron affinity of fluorine-terminated (100) diamond surfaces prepared by exposure to dissociated XeF2 have been determined using synchrotron-based photoemission. After vacuum annealing 350 °C a clean, monofluoride terminated C(100):F surface was obtained for which an 2.56 eV measured. This is the highest reported any termination so far, it exceeds value predicted recent density functional theory calculations 0.43 eV. 7.24 measured same places Fermi energy 0.79 above...
Diamond surface termination with substitutional nitrogen is reported, leading to the formation of a stable which essentially clear sub-band states and has positive electron affinity. This predicted be an ideal environment for near-surface nitrogen-vacancy centers in diamond may enable magnetic quantum sensing breakthroughs these devices. As service our authors readers, this journal provides supporting information supplied by authors. Such materials are peer reviewed re-organized online...
Surface sensitive C1s core level photoelectron spectroscopy was used to examine the electronic properties of C(60)F(48) molecules on C(100):H surface. An upward band bending 0.74 eV in response surface transfer doping by fluorofullerene is measured. Two distinct molecular charge states are identified and their relative concentration determined as a function coverage. One corresponds ionized that participate other neutral do not. The position lowest unoccupied orbital which relevant acceptor...
Abstract The presence of an air‐stable negative electron affinity (NEA) on lithium‐covered oxygen‐terminated diamond after a thermal activation process is demonstrated. NEA unequivocally established by the onset photoelectron yield at bandgap energy 5.5 eV. This surface exhibits secondary enhancement factor 200, compared to with positive affinity. chemistry leading necessary dipole was elucidated core‐level photoemission spectroscopy in conjunction previous theoretical calculations....
Hydrogen-terminated diamond possesses due to transfer doping a quasi-two-dimensional (2D) hole accumulation layer at the surface with strong, Rashba-type spin–orbit coupling that arises from highly asymmetric confinement potential. By modulating concentration and thus potential using an electrostatic gate ionic-liquid dielectric architecture splitting can be tuned 4.6–24.5 meV concurrent spin relaxation length of 33–16 nm sheet densities up 7.23 × 1013 cm–2. This demonstrates interaction...
We report large negative electron affinity (NEA) on diamond (100) using magnesium adsorption a previously oxygen-terminated surface. The measured NEA is up to $(\ensuremath{-}2.01\ifmmode\pm\else\textpm\fi{}0.05)$ eV, the largest reported date. Despite expected close relationship between surface chemistry of Mg and Li species diamond, we observe differences in properties two. Most importantly, high-temperature annealing step not required activate Mg-adsorbed state affinity. Diamond surfaces...
The electronic structure of physisorbed molecules containing aromatic nitrogen heterocycles (triazine and melamine) on graphene is studied.
Hydrogenated diamond possesses a unique surface conductivity as result of transfer doping by acceptors. Yet, despite being extensively studied for the past two decades, little is known about system at low temperature, particularly whether two-dimensional hole gas forms surface. Here we report that (100) diamond, when functionalized with hydrogen, supports p-type spin-3/2 spin–orbit interaction 9.74 ± 0.1 meV through observation weak antilocalization effects in magneto-conductivity...
We report the preparation of an ordered silicon terminated diamond (100) surface with a two domain 3 × 1 reconstruction as determined by low energy electron diffraction. Based on dimensions unit cell and chemical information provided core level photoemission spectra, model for structure is proposed. The termination should provide homogeneous, nuclear, spin-free development future near-surface quantum device architectures.
The use of a transition metal catalyzed thermochemical etching method for improving the carrier transport properties near-surface two-dimensional (2D) hole gas in surface transfer-doped hydrogen-terminated (111) diamond is demonstrated. Using Ni0.8Cr0.2 films deposited and annealed to temperature 900 °C, with up three etch cycles, preferential produces large terraces exceeding 10 μm size microroughness, σRMS2λ, that two orders magnitude lower than pre-etched surface. Magnetotransport...
We review progress at the Australian Centre for Quantum Computer Technology towards fabrication and demonstration of spin qubits charge based on phosphorus donor atoms embedded in intrinsic silicon. Fabrication is being pursued via two complementary pathways: a 'top-down' approach near-term production few-qubit devices 'bottom-up' large-scale qubit arrays with sub-nanometre precision. The employs low-energy (keV) ion beam to implant atoms. Single-atom control during implantation achieved by...
We demonstrate that the intrinsic electron doping of monolayer epitaxial graphene on SiC(0001) can be tuned in a controlled fashion to holes via molecular with fluorinated fullerene C60F48. In situ angle-resolved photoemission is used measure an upward shift (0.6 ± 0.05) eV Dirac point from −0.43 +0.17 relative Fermi level. The carrier density observed change n ∼ (1 × 1013 0.1 1013) cm−2 p (2 1012 1 1012) cm−2. introduce model employing Fermi-Dirac statistics which explicitly takes...
This paper reviews electron emission from negative affinity (NEA) diamond and gives account of the recent developments in alternatives to hydrogen‐termination for producing NEA surfaces, particularly using lithium on oxygen‐terminated diamond. We discuss background motivation alkali metals present both experimental computational results that cover structure, electronic properties, photoemission, total photoyield. Secondary yield enhancement over 200 × is demonstrated a reference surface with...
A combination of synchrotron-based x-ray spectroscopy and contact potential difference measurements have been used to examine the electronic structure (3 × 1) silicon terminated (100) diamond surface under ultra high vacuum conditions. An occupied state which sits 1.75 eV below valence band maximum has identified, indications mid-gap unoccupied states found. Additionally, pristine is shown possess a negative electron affinity −0.86 ± 0.1 eV.
The p-type surface conductivity of hydrogen-terminated diamond (H-diamond) provides a viable approach toward diamond-based wide-bandgap metal-oxide-semiconductor field-effect transistors (MOSFETs) for high-power and high-frequency electronics. A facile, low-cost, low-temperature method to form gate dielectrics on that also preserves the integrity hydrogen-termination is highly desirable high-performance electronics with process flexibility high yield. In this work, we demonstrate p-channel...
In this paper we examine the effects of varying several experimental parameters in Kane quantum computer architecture: A-gate voltage, qubit depth below silicon oxide barrier, and back gate to explore how these variables affect electron density donor electron. particular, calculate resonance frequency nuclei as a function parameters. To do calculated wave variationally using an effective-mass Hamiltonian approach, basis deformed hydrogenic orbitals. This approach was then extended include...
A self-consistent one-dimensional solution of the Poisson and Schr\"odinger equations is developed to describe electronic properties hole gas confined below hydrogen-terminated surface conducting diamond. The energy eigenstates confinement potential position Fermi level are examined as a function carrier sheet density temperature. comparison made with experimental studies for both atmosphere-induced synthetic acceptors. For densities $9\ifmmode\times\else\texttimes\fi{}{10}^{12}\text{...