A5062572766- Graphene research and applications
- Terahertz technology and applications
- Semiconductor materials and devices
- Metamaterials and Metasurfaces Applications
- Advanced biosensing and bioanalysis techniques
- Microwave and Dielectric Measurement Techniques
- Plasmonic and Surface Plasmon Research
- Molecular Junctions and Nanostructures
- Nanowire Synthesis and Applications
- 2D Materials and Applications
- MXene and MAX Phase Materials
- Photonic and Optical Devices
- Diamond and Carbon-based Materials Research
- Advancements in Battery Materials
- Electron and X-Ray Spectroscopy Techniques
- Photonic Crystals and Applications
- Quantum and electron transport phenomena
- Advanced Electron Microscopy Techniques and Applications
- Superconducting and THz Device Technology
- Copper-based nanomaterials and applications
- Lysosomal Storage Disorders Research
- Electronic and Structural Properties of Oxides
- ZnO doping and properties
- Nanopore and Nanochannel Transport Studies
- Optical Coatings and Gratings
University of Cambridge
2019-2025
Abstract Solar fuels offer a promising approach to provide sustainable by harnessing sunlight 1,2 . Following decade of advancement, Cu 2 O photocathodes are capable delivering performance comparable that photoelectrodes with established photovoltaic materials 3–5 However, considerable bulk charge carrier recombination is poorly understood still limits further advances in 6 Here we demonstrate beyond the state-of-the-art exploiting new conceptual understanding and transport single-crystal...
Hexagonal boron nitride (hBN) is a promising host material for room-temperature, tunable solid-state quantum emitters. A key technological challenge deterministic and scalable spatial emitter localization, both laterally vertically, while maintaining the full advantages of 2D nature material. Here, we demonstrate localization in hBN all three dimensions via monolayer (ML) engineering approach. We establish pretreatment processes MLs to either fully suppress or activate emission, thereby...
Membranes that selectively filter for both anions and cations are central to technological applications from clean energy generation desalination devices. 2D materials have immense potential as these ion-selective membranes due their thinness, mechanical strength, tunable surface chemistry; however, currently, only cation-selective been reported. Here we demonstrate the controllable cation anion selectivity of monolayer graphene hexagonal boron nitride. In particular, measure ionic current...
Hexagonal boron nitride (h-BN) is the only known material aside from graphite with a structure composed of simple, stable, noncorrugated atomically thin layers. While historically used as lubricant in powder form, h-BN layers have become particularly attractive an ultimately insulator, barrier, or encapsulant. Practically all emerging electronic and photonic device concepts currently rely on exfoliated small bulk crystallites, which limits dimensions process scalability. We here focus...
Reliable, clean transfer and interfacing of 2D material layers is technologically as important their growth. Bringing both together remains a challenge due to the vast, interconnected parameter space. We introduce fast-screening descriptor approach demonstrate holistic data-driven optimization across entirety process steps for graphene-Cu model system. map crystallographic dependencies graphene chemical vapor deposition, interfacial Cu oxidation decouple graphene, its dry delamination...
We report on an approach to bring together single crystal metal catalyst preparation and graphene growth in a combined process flow using standard cold-wall chemical vapor deposition (CVD) reactor. employ sandwich arrangement between commercial polycrystalline Cu foil c-plane sapphire wafer show that close-spaced vacuum sublimation across the confined gap can result epitaxial, single-crystal Cu(111) film at high rate. The is scalable (we demonstrate 2″ scale) suppresses reactor contamination...
All-electronicultrafast control of terahertz radiation is demonstrated in integrated metamaterial/graphene devices. By electrostatic gating the graphene conductivity, overall optical response incident <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$E$</tex-math></inline-formula> -field modified. Depending on configuration, amplitude, phase, and polarization could be modulated with GHz range reconfiguration...
We systematically study the effects of residual oxygen in bulk Cu foil catalysts on chemical vapor deposition (CVD) graphene. While oxidation is widely used to remove impurities metal and control nucleation density graphene, we show that minute concentrations can significantly deteriorate quality as-grown graphene highlighted by an increased Raman D/G ratio, propensity postgrowth etching, fraction multilayer nucleation. Starting from commercial foils, a simple hydrogen annealing step after...
We demonstrate how terahertz time-domain spectroscopy (THz-TDS) operating in reflection geometry can be used for quantitative conductivity mapping of large area chemical vapor deposited graphene films through silicon support. validate the technique against measurements performed using established transmission based THz-TDS. Our through-substrate approach allows unhindered access to top surface and thus, as we discuss, opens up pathways perform situ in-operando THz-TDS environmental cells.
We combine spatially resolved scanning photoelectron spectroscopy with confocal Raman and optical microscopy to reveal how the oxidation of buried graphene–Cu interface relates Cu crystallographic orientation. analyze over 100 different graphene covered (high low index) orientations exposed air for 2 years. Four general modes are observed that can be mapped as regions onto polar plot surface orientations. These (1) complete, (2) irregular, (3) inhibited, (4) enhanced wrinkle oxidation....
Abstract Simultaneously recording network activity and ultrastructural changes of the synapse is essential for advancing understanding basis neuronal functions. However, rapid millisecond‐scale fluctuations in subtle sub‐diffraction resolution synaptic morphology pose significant challenges to this endeavor. Here, specially designed graphene microelectrode arrays (G‐MEAs) are used, which compatible with high spatial imaging across various scales as well permit temporal electrophysiological...
Twisted bilayer graphene provides an ideal solid-state model to explore correlated material properties and opportunities for a variety of optoelectronic applications, but reliable, fast characterization the twist angle remains challenge. Here we introduce spectroscopic ellipsometric contrast microscopy (SECM) as tool mapping disorder in optically resonant twisted graphene. We optimize angles enhance image based on measured calculated reflection coefficients incident light. The optical...
Abstract Hexagonal boron nitride (h-BN) is well-established as a requisite support, encapsulant and barrier for 2D material technologies, but also recently an active applications ranging from hyperbolic metasurfaces to room temperature single-photon sources. Cost-effective, scalable high quality growth techniques h-BN layers are critically required. We utilise widely-available iron foils the catalytic chemical vapour deposition (CVD) of report on significant role bulk dissolved species in...
We explore a number of different electrochemical, wet chemical, and gas phase approaches to study intercalation oxidation at the buried graphene-Ge interface. While previous literature focused on passivation Ge surface by chemical vapor deposited graphene, we show that particularly via electrochemical in 0.25 N solution anhydrous sodium acetate glacial acetic acid, this can be overcome grow GeO2 under graphene. Angle resolved photoemission spectroscopy, Raman He ion microscopy,...
A deconstructed MOCVD model process allows in-<italic>operando</italic> fingerprinting of the chemical reactions that underpin WS2 monolayer crystal growth, and highlights enhancing role Au support in conjunction with simple organosulfide precursors.
Identification of non-amplified DNA sequences and single-base mutations is essential for molecular biology genetic diagnostics. This paper reports a novel sensor consisting electrochemically-gated graphene coplanar waveguides coupled with microfluidic channel. Upon exposure to analytes, propagation electromagnetic waves in the modified as result interactions fringing field modulation dynamic conductivity resulting from electrostatic gating. Probe are immobilised on surface, exposed which...
Abstract Simultaneously recording network activity and ultrastructural changes of the synapse is essential for advancing our understanding basis neuronal functions. However, rapid millisecond-scale fluctuations in subtle sub-diffraction resolution synaptic morphology pose significant challenges to this endeavour. Here, we use graphene microelectrode arrays (G-MEAs) address these challenges, as they are compatible with high spatial imaging across various scales well temporal...
Abstract A novel approach is demonstrated to identify glucose concentration in aqueous solutions based on the combined effect of its frequency‐dependent interaction with microwaves propagating graphene channels and modification radio frequency (RF) conductivity caused by physisorbed molecules. This combines broadband microwave sensing chemical field transistor a single device, leading information‐rich, multidimensional datasets form scattering parameters. sensitivity 7.30 dB(mg/L) −1...
We report on the ultrafast modulation of a graphene loaded artificial metasurface realized SiO2/Si substrate by near-IR laser pump, detected via terahertz probe at resonant frequency ∼0.8 THz. The results have been acquired setting Fermi energy Dirac point electrostatic gating and illuminating sample with 40 fs pump pulses different fluences, ranging from 0.9 to 0.018 mJ/cm2. sub-ps conductivity rising time was attributed combined effect generation hot carriers in electron–hole silicon. In...
We present a high-throughput method for identifying and characterizing individual nanowires automatically designing electrode patterns with high alignment accuracy. Central to our is an optimized machine-readable, lithographically processable, multi-scale fiducial marker system─dubbed LithoTag─which provides nanostructure position determination at the nanometer scale. A grid of uniquely defined LithoTag markers patterned across substrate enables image mapping in 100% set >9000 scanning...
Active modification of the polarization state is a key feature for next-generation wireless communications, sensing, and imaging in THz band. The modulation performance an integrated metamaterial/graphene device investigated via modified time domain spectroscopic system. Graphene’s Fermi level through electrostatic gating, thus modifying device’s overall optical response. tuning ellipticity by <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="m1"><mml:mo>></mml:mo></mml:math>...
Remote epitaxy is an emerging materials synthesis technique which employs a 2D interface layer, often graphene, to enable the epitaxial deposition of low defect single crystal films while restricting bonding between growth layer and underlying substrate. This allows for subsequent release film integration with other systems reuse substrates. approach applicable material ionic component their bonding, making it notably appealing III-V alloys, are technologically important family materials....
We present multiplexer methodology and hardware for nanoelectronic device characterization. This high-throughput scalable approach to testing large arrays of nanodevices operates from room temperature milli-Kelvin temperatures is universally compatible with different materials integration techniques. demonstrate the applicability our on two archetypal nanomaterials—graphene semiconductor nanowires—integrated a GaAs-based using wet or dry transfer methods. A graphene film grown by chemical...
We report the growth, structural and magnetic properties of less studied Eu-oxide phase, Eu$_3$O$_4$, thin films grown on a Si/SiO$_2$ substrate Si/SiO$_2$/graphene using molecular beam epitaxy. The X-ray diffraction scans show that highly-textured crystalline Eu$_3$O$_4$(001) are both substrates, whereas film deposited graphene has better crystallinity than substrate. SQUID measurements have Curie temperature about 5.5 K, with moment 0.0032 emu/g at 2 K. mixed-valency Eu cations been...