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Step-Flow Growth of Graphene-Boron Nitride Lateral Heterostructures by Molecular Beam Epitaxy (2020)
Journal Article
Thomas, J., Bradford, J., Cheng, T. S., Summerfield, A., Wrigley, J., Mellor, C. J., …Beton, P. H. (2020). Step-Flow Growth of Graphene-Boron Nitride Lateral Heterostructures by Molecular Beam Epitaxy. 2D Materials, 7(3), https://doi.org/10.1088/2053-1583/ab89e7

Integration of graphene and hexagonal boron nitride (hBN) into lateral heterostructures has drawn focus due to the ability to broadly engineer the material properties. Hybrid monolayers with tuneable bandgaps have been reported, while the interface i... Read More about Step-Flow Growth of Graphene-Boron Nitride Lateral Heterostructures by Molecular Beam Epitaxy.

Direct band-gap crossover in epitaxial monolayer boron nitride (2019)
Journal Article
Elias, C., Valvin, P., Pelini, T., Summerfield, A., Mellor, C., Cheng, T., …Cassabois, G. (2019). Direct band-gap crossover in epitaxial monolayer boron nitride. Nature Communications, 10, https://doi.org/10.1038/s41467-019-10610-5

Hexagonal boron nitride is a large band-gap insulating material which complements the electronic and optical properties of graphene and the transition metal dichalcogenides. However, the intrinsic optical properties of monolayer boron nitride remain... Read More about Direct band-gap crossover in epitaxial monolayer boron nitride.

Photo-quantum Hall effect and light-induced charge transfer at the interface of graphene/InSe heterostructures (2018)
Journal Article
Bhuiyan, M. A., Kudrynskyi, Z. R., Mazumder, D., Greener, J. D., Makarovsky, O., Mellor, C. J., …Patanè, A. (2019). Photo-quantum Hall effect and light-induced charge transfer at the interface of graphene/InSe heterostructures. Advanced Functional Materials, 29(3), https://doi.org/10.1002/adfm.201805491

The transfer of electronic charge across the interface of two van der Waals crystals can underpin the operation of a new class of functional devices. Amongst van der Waals semiconductors, an exciting and rapidly growing development involves the “post... Read More about Photo-quantum Hall effect and light-induced charge transfer at the interface of graphene/InSe heterostructures.

High-temperature molecular beam epitaxy of hexagonal boron nitride with high active nitrogen fluxes (2018)
Journal Article
Cheng, T. S., Summerfield, A., Mellor, C. J., Khlobystov, A. N., Eaves, L., Foxon, C. T., …Novikov, S. V. (2018). High-temperature molecular beam epitaxy of hexagonal boron nitride with high active nitrogen fluxes. Materials, 11(7), https://doi.org/10.3390/ma11071119

Hexagonal boron nitride (hBN) has attracted much attention as a key component in van der Waals heterostructures and as a wide band gap material for deep-ultraviolet devices. We have recently demonstrated plasma-assisted molecular beam epitaxy (PA-MBE... Read More about High-temperature molecular beam epitaxy of hexagonal boron nitride with high active nitrogen fluxes.

Moiré-modulated conductance of hexagonal boron nitride tunnel barriers (2018)
Journal Article
Summerfield, A., Kozikov, A., Cheng, T. S., Davies, A., Cho, Y., Khlobystov, A. N., …Beton, P. H. (in press). Moiré-modulated conductance of hexagonal boron nitride tunnel barriers. Nano Letters, doi:10.1021/acs.nanolett.8b01223

Monolayer hexagonal boron nitride (hBN) tunnel barriers investigated using conductive atomic force microscopy reveal moiré patterns in the spatial maps of their tunnel conductance consistent with the formation of a moiré superlattice between the hB... Read More about Moiré-modulated conductance of hexagonal boron nitride tunnel barriers.

Photoelastic properties of zinc-blende (AlGa)N in the UV: picosecond ultrasonic studies (2018)
Journal Article
Whale, J., Akimov, A. V., Novikov, S. V., Mellor, C. J., & Kent, A. J. (2018). Photoelastic properties of zinc-blende (AlGa)N in the UV: picosecond ultrasonic studies. Physical Review Materials, 2(3), https://doi.org/10.1103/PhysRevMaterials.2.034606

Picosecond ultrasonics was used to study the photoelastic properties of zinc-blende (cubic) c-AlₓGa₁₋ₓN with x around 0.5 The velocities for longitudinal sound in the alloys were measured using ultrafast UV pump-probe experiments with (Al... Read More about Photoelastic properties of zinc-blende (AlGa)N in the UV: picosecond ultrasonic studies.

High-temperature molecular beam epitaxy of hexagonal boron nitride layers (2018)
Journal Article
Cheng, T. S., Summerfield, A., Mellor, C. J., Davies, A., Khlobystov, A. N., Eaves, L., …Novikov, S. V. (in press). High-temperature molecular beam epitaxy of hexagonal boron nitride layers. Journal of Vacuum Science and Technology B, 36(2), https://doi.org/10.1116/1.5011280

The growth and properties of hexagonal boron nitride (hBN) have recently attracted much attention due to applications in graphene-based monolayer thick 2D-structures and at the same time as a wide band gap material for deep-ultraviolet device (DUV) a... Read More about High-temperature molecular beam epitaxy of hexagonal boron nitride layers.

Lattice-matched epitaxial graphene grown on boron nitride (2017)
Journal Article
Davies, A., Albar, J., Summerfield, A., Thomas, J. C., Cheng, T. S., Korolkov, V. V., …Beton, P. H. (2018). Lattice-matched epitaxial graphene grown on boron nitride. Nano Letters, 18(1), https://doi.org/10.1021/acs.nanolett.7b04453

Lattice-matched graphene on hexagonal boron nitride is expected to lead to the formation of a band-gap but requires the formation of highly strained material and has not hitherto been realised. We demonstrate that aligned, lattice-matched graphene ca... Read More about Lattice-matched epitaxial graphene grown on boron nitride.

Magnetic field tunable vortex diode made of YBa2Cu3O7−δ Josephson junction asymmetrical arrays (2017)
Journal Article
Chesca, B., John, D., Pollett, R., Gaifullin, M., Cox, J., Mellor, C., & Savelev, S. (in press). Magnetic field tunable vortex diode made of YBa2Cu3O7−δ Josephson junction asymmetrical arrays. Applied Physics Letters, 111(6), doi:10.1063/1.4997741

Several Josephson ratchets designed as asymmetrically structured parallel-series arrays of Josephson junctions made of YBa2Cu3O7−δ have been fabricated. From the current-voltage characteristics measured for various values of applied magnetic field, B... Read More about Magnetic field tunable vortex diode made of YBa2Cu3O7−δ Josephson junction asymmetrical arrays.

Microwave Generation in Synchronized Semiconductor Superlattices (2017)
Journal Article
Gaifullin, M., Alexeeva, N., Hramov, A., Makarov, V., Maksimenko, V., Koronovskii, A., …Balanov, A. (2017). Microwave Generation in Synchronized Semiconductor Superlattices. Physical Review Applied, 7(4), https://doi.org/10.1103/PhysRevApplied.7.044024

We study high-frequency generation in a system of electromagnetically coupled semiconductor superlattices fabricated on the same doped substrate. Applying a bias voltage to a single superlattice generates high-frequency current oscillations. We demon... Read More about Microwave Generation in Synchronized Semiconductor Superlattices.

Hexagonal Boron Nitride Tunnel Barriers Grown on Graphite by High Temperature Molecular Beam Epitaxy (2016)
Journal Article
Cho, Y., Summerfield, A., Davies, A., Cheng, T. S., Smith, E. F., Mellor, C. J., …Novikov, S. V. (2016). Hexagonal Boron Nitride Tunnel Barriers Grown on Graphite by High Temperature Molecular Beam Epitaxy. Scientific Reports, 6(1), https://doi.org/10.1038/srep34474

We demonstrate direct epitaxial growth of high-quality hexagonal boron nitride (hBN) layers on graphite using high-temperature plasma-assisted molecular beam epitaxy. Atomic force microscopy reveals mono- and few-layer island growth, while conducting... Read More about Hexagonal Boron Nitride Tunnel Barriers Grown on Graphite by High Temperature Molecular Beam Epitaxy.

The UK National Quantum Technologies Hub in sensors and metrology (Keynote Paper) (2016)
Journal Article
Bongs, K., Boyer, V., Cruise, M., Freise, A., Holynski, M., Hughes, J., …John, P. (2016). The UK National Quantum Technologies Hub in sensors and metrology (Keynote Paper). Proceedings of SPIE, 9900, https://doi.org/10.1117/12.2232143

The UK National Quantum Technology Hub in Sensors and Metrology is one of four flagship initiatives in the UK National of Quantum Technology Program. As part of a 20-year vision it translates laboratory demonstrations to deployable practical devices,... Read More about The UK National Quantum Technologies Hub in sensors and metrology (Keynote Paper).

Strain-Engineered Graphene Grown on Hexagonal Boron Nitride by Molecular Beam Epitaxy (2016)
Journal Article
Summerfield, A., Davies, A., Cheng, T. S., Korolkov, V. V., Cho, Y., Mellor, C. J., …Beton, P. H. (2016). Strain-Engineered Graphene Grown on Hexagonal Boron Nitride by Molecular Beam Epitaxy. Scientific Reports, 6(1), https://doi.org/10.1038/srep22440

Graphene grown by high temperature molecular beam epitaxy on hexagonal boron nitride (hBN) forms continuous domains with dimensions of order 20 μm, and exhibits moiré patterns with large periodicities, up to ~30 nm, indicating that the layers are hig... Read More about Strain-Engineered Graphene Grown on Hexagonal Boron Nitride by Molecular Beam Epitaxy.

High temperature MBE of graphene on sapphire and hexagonal boron nitride flakes on sapphire (2016)
Journal Article
Cheng, T. S., Davies, A., Summerfield, A., Cho, Y., Cebula, I., Hill, R. J., …Novikov, S. V. (2016). High temperature MBE of graphene on sapphire and hexagonal boron nitride flakes on sapphire. Journal of Vacuum Science and Technology B, 34(2), 02L101. https://doi.org/10.1116/1.4938157

The discovery of graphene and its remarkable electronic properties has provided scientists with a revolutionary material system for electronics and optoelectronics. Here, the authors investigate molecular beam epitaxy (MBE) as a growth method for gra... Read More about High temperature MBE of graphene on sapphire and hexagonal boron nitride flakes on sapphire.

Design, fabrication and demonstration of a 1x20 multimode interference splitter for parallel biosensing applications (2016)
Journal Article
Najeeb, N., Zhang, Y., Mellor, C. J., & Benson, T. M. (2016). Design, fabrication and demonstration of a 1x20 multimode interference splitter for parallel biosensing applications. Journal of Physics: Conference Series, 679(1), doi:10.1088/1742-6596/679/1/012027

This paper presents the experimental achievement of a silicon-on-insulator 1x20 MMI splitter andsimulation evaluations of the TE-like and TM-like mode MMI splitters for parallel biosensing applications. Device fabrication technology and optical chara... Read More about Design, fabrication and demonstration of a 1x20 multimode interference splitter for parallel biosensing applications.

Photonic biosensor chip for early-stage cancer diagnosis (2015)
Conference Proceeding
Najeeb, N., Zhang, Y., Mellor, C. J., & Benson, T. M. (2015). Photonic biosensor chip for early-stage cancer diagnosis. In 2015 17th International Conference on Transparent Optical Networks (ICTON)doi:10.1109/ICTON.2015.7193316

This paper introduces a generic design of a silicon on silica “lab on a chip” photonic biosensor for medical diagnosis applications, and especially for early-stage cancer diagnosis. The sensitivity of detection of the biosensor developed is at least... Read More about Photonic biosensor chip for early-stage cancer diagnosis.

Ligand-Induced Control of Photoconductive Gain and Doping in a Hybrid Graphene-Quantum Dot Transistor (2015)
Journal Article
Turyanska, L., Makarovsky, O., Svatek, S. A., Beton, P. H., Mellor, C. J., Patanè, A., …Wilson, N. R. (2015). Ligand-Induced Control of Photoconductive Gain and Doping in a Hybrid Graphene-Quantum Dot Transistor. Advanced Electronic Materials, 1(7), 1500062. https://doi.org/10.1002/aelm.201500062

In graphene devices decorated with a layer of near-infrared colloidal PbS quantum dots (QDs), the choice of the QD capping ligands and the integrity of the QD layer have a strong influence on the doping, carrier mobility, and photoresponse. By using... Read More about Ligand-Induced Control of Photoconductive Gain and Doping in a Hybrid Graphene-Quantum Dot Transistor.

High Broad-Band Photoresponsivity of Mechanically Formed InSe-Graphene van der Waals Heterostructures (2015)
Journal Article
Mudd, G. W., Svatek, S. A., Hague, L., Makarovsky, O., Kudrynskyi, Z. R., Mellor, C. J., …Patanè, A. (2015). High Broad-Band Photoresponsivity of Mechanically Formed InSe-Graphene van der Waals Heterostructures. Advanced Materials, 27(25), 3760-3766. https://doi.org/10.1002/adma.201500889

We exploit the broad-band transparency of graphene and the favorable band line up of graphene with van der Waals InSe crystals to create new functional heterostructures and high-performance photodetectors. The InSe-graphene heterostructure exhibits a... Read More about High Broad-Band Photoresponsivity of Mechanically Formed InSe-Graphene van der Waals Heterostructures.

III-V semiconductor waveguides for photonic functionality at 780 nm (2014)
Journal Article
Maclean, J. O., Greenaway, M. T., Campion, R. P., Pyragius, T., Fromhold, T. M., Kent, A. J., & Mellor, C. J. (2014). III-V semiconductor waveguides for photonic functionality at 780 nm. Proceedings of SPIE, 8988, https://doi.org/10.1117/12.2039898

Photonic integrated circuits based on III-V semiconductor polarization-maintaining waveguides were designed and fabricated for the first time for application in a compact cold-atom gravimeter1,2 at an operational wavelength of 780 nm. Compared with o... Read More about III-V semiconductor waveguides for photonic functionality at 780 nm.


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