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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-Al?Ga???N 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), Article 02D103-1. 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), 498-504. 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?? 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?? Josephson junction asymmetrical arrays. Applied Physics Letters, 111(6), https://doi.org/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?? 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), Article 044024. 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), Article 34474. 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, Article 990009. 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), Article 22440. 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), https://doi.org/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.

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.

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.

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, Article 898805. 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.

Nonlinear modal coupling in a high-stress doubly-clamped nanomechanical resonator (2012)
Journal Article
Lulla, K., Cousins, R., Venkatesan, A., Patton, M., Armour, A., Mellor, C. J., & Owers-Bradley, J. (2012). Nonlinear modal coupling in a high-stress doubly-clamped nanomechanical resonator. New Journal of Physics, 14, Article 113040. https://doi.org/10.1088/1367-2630/14/11/113040

We present results from a study of the nonlinear inter-modal coupling between different flexural vibrational modes of a single high-stress, doubly-clamped silicon nitride nanomechanical beam. Using the magnetomotive technique and working at 100 mK we... Read More about Nonlinear modal coupling in a high-stress doubly-clamped nanomechanical resonator.

Scanning capacitance imaging of compressible and incompressible quantum Hall effect edge strips (2012)
Journal Article
Suddards, M., Baumgartner, A., Henini, M., & Mellor, C. J. (2012). Scanning capacitance imaging of compressible and incompressible quantum Hall effect edge strips. New Journal of Physics, 14, Article 08315. https://doi.org/10.1088/1367-2630/14/8/083015

We use dynamic scanning capacitance microscopy to image compressible and incompressible strips at the edge of a Hall bar in a two-dimensional electron gas (2DEG) in the quantum Hall effect (QHE) regime. This method gives access to the complex local c... Read More about Scanning capacitance imaging of compressible and incompressible quantum Hall effect edge strips.