All Outputs (24)

Acoustic band engineering in terahertz quantum-cascade lasers and arbitrary superlattices (2023)
Journal Article
Demić, A., Valavanis, A., Dean, P., Li, L., Davies, A. G., Linfield, E. H., …Harrison, P. (2023). Acoustic band engineering in terahertz quantum-cascade lasers and arbitrary superlattices. Physical Review B, 107(23), Article 235411. https://doi.org/10.1103/physrevb.107.235411

We present theoretical methods for the analysis of acoustic phonon modes in superlattice structures, and terahertz-frequency quantum-cascade lasers (THz QCLs). Our generalized numerical solution of the acoustic-wave equation provides good agreement w... Read More about Acoustic band engineering in terahertz quantum-cascade lasers and arbitrary superlattices.

Coherent Phononics of van der Waals Layers on Nanogratings (2022)
Journal Article
Yan, W., Akimov, A. V., Barra-Burillo, M., Bayer, M., Bradford, J., Gusev, V. E., …Linnik, T. L. (2022). Coherent Phononics of van der Waals Layers on Nanogratings. Nano Letters, 22(16), 6509-6515. https://doi.org/10.1021/acs.nanolett.2c01542

Strain engineering can be used to control the physical properties of two-dimensional van der Waals (2D-vdW) crystals. Coherent phonons, which carry dynamical strain, could push strain engineering to control classical and quantum phenomena in the unex... Read More about Coherent Phononics of van der Waals Layers on Nanogratings.

Luminescence and Crystalline Properties of InGaN-based LED on Si Substrate with AlN/GaN Superlattice Structure (2021)
Journal Article
Alias, E. A., Taib, M. I. M., Bakar, A. S. A., Egawa, T., Kent, A. J., Kamil, W. M. W. A., & Zainal, N. (2021). Luminescence and Crystalline Properties of InGaN-based LED on Si Substrate with AlN/GaN Superlattice Structure. Journal of Physical Science, 32(3), 1-11. https://doi.org/10.21315/jps2021.32.3.1

A crack-free indium gallium nitride (InGaN) based light emitting diode (LED) grown on silicon (Si) substrate was successfully demonstrated by introducing aluminium nitride/gallium nitride (AlN/GaN) superlattice structure (SLS) in the growth of the LE... Read More about Luminescence and Crystalline Properties of InGaN-based LED on Si Substrate with AlN/GaN Superlattice Structure.

Nondestructive Picosecond Ultrasonic Probing of Intralayer and van der Waals Interlayer Bonding in α- and β-In2Se3 (2021)
Journal Article
Yan, W., Akimov, A. V., Page, J. A., Greenaway, M. T., Balanov, A. G., Patanè, A., & Kent, A. J. (2021). Nondestructive Picosecond Ultrasonic Probing of Intralayer and van der Waals Interlayer Bonding in α- and β-In2Se3. Advanced Functional Materials, 31(50), Article 2106206. https://doi.org/10.1002/adfm.202106206

The interplay between the strong intralayer covalent-ionic bonds and the weak interlayer van der Waals (vdW) forces between the neighboring layers of vdW crystals gives rise to unique physical and chemical properties. Here, the intralayer and interla... Read More about Nondestructive Picosecond Ultrasonic Probing of Intralayer and van der Waals Interlayer Bonding in α- and β-In2Se3.

Performance evaluation of a new 30 ?m thick GaAs X-ray detector grown by MBE (2021)
Journal Article
Lioliou, G., Poyser, C. L., Whale, J., Campion, R. P., Kent, A. J., & Barnett, A. (2021). Performance evaluation of a new 30 ?m thick GaAs X-ray detector grown by MBE. Materials Research Express, 8(2), Article 025909. https://doi.org/10.1088/2053-1591/abe73c

A circular mesa (400 μm diameter) GaAs p+-i-n+ photodiode with a 30 μm thick i layer was characterized for its performance as a detector in photon counting x-ray spectroscopy at 20 °C. The detector was fabricated from material grown by molecular beam... Read More about Performance evaluation of a new 30 ?m thick GaAs X-ray detector grown by MBE.

Low-energy switching of antiferromagnetic CuMnAs/GaP using sub-10 nanosecond current pulses (2020)
Journal Article
Omari, K. A., Barton, L. X., Amin, O., Campion, R. P., Rushforth, A. W., Kent, A. J., …Edmonds, K. W. (2020). Low-energy switching of antiferromagnetic CuMnAs/GaP using sub-10 nanosecond current pulses. Journal of Applied Physics, 127(19), Article 193906. https://doi.org/10.1063/5.0006183

The recently discovered electrical-induced switching of antiferromagnetic (AF) materials that have spatial inversion asymmetry has enriched the field of spintronics immensely and opened the door for the concept of antiferromagnetic memory devices. Cu... Read More about Low-energy switching of antiferromagnetic CuMnAs/GaP using sub-10 nanosecond current pulses.

Temporal superoscillations of subterahertz coherent acoustic phonons (2020)
Journal Article
Brehm, S., Akimov, A. V., Campion, R. P., & Kent, A. J. (2020). Temporal superoscillations of subterahertz coherent acoustic phonons. Physical Review Research, 2(2), Article 023009. https://doi.org/10.1103/physrevresearch.2.023009

We observe coherent acoustic phonon superoscillations at subterahertz frequencies. The superoscillations result from the interference of optically excited coherent longitudinal acoustic phonon modes in a GaAs/AlGaAs superlattice. The superoscillation... Read More about Temporal superoscillations of subterahertz coherent acoustic phonons.

High-speed modulation of a terahertz quantum cascade laser by coherent acoustic phonon pulses (2020)
Journal Article
Dunn, A., Poyser, C., Dean, P., Demić, A., Valavanis, A., Indjin, D., …Kent, A. (2020). High-speed modulation of a terahertz quantum cascade laser by coherent acoustic phonon pulses. Nature Communications, 11, Article 835. https://doi.org/10.1038/s41467-020-14662-w

The fast modulation of lasers is a fundamental requirement for applications in optical communications, high-resolution spectroscopy and metrology. In the terahertz-frequency range, the quantum-cascade laser (QCL) is a high-power source with the poten... Read More about High-speed modulation of a terahertz quantum cascade laser by coherent acoustic phonon pulses.

30 μm thick GaAs X-ray p + -i-n + photodiode grown by MBE (2019)
Journal Article
Lioliou, G., Poyser, C., Butera, S., Campion, R., Kent, A., & Barnett, A. (2019). 30 μm thick GaAs X-ray p + -i-n + photodiode grown by MBE. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 946, Article 162670. https://doi.org/10.1016/j.nima.2019.162670

7 8 A GaAs p +-in + photodiode detector with a 30 μm thick i layer and a 400 μm diameter was processed using 9 standard wet chemical etching from material grown by molecular beam epitaxy. The detector was 10 characterized for its electrical and photo... Read More about 30 μm thick GaAs X-ray p + -i-n + photodiode grown by MBE.

A high electron mobility phonotransistor (2018)
Journal Article
Poyser, C. L., Li, L. H., Campion, R. P., Akimov, A. V., Linfield, E. H., Davies, A. G., …Kent, A. J. (2018). A high electron mobility phonotransistor. Communications Physics, 1, 1-7. https://doi.org/10.1038/s42005-018-0059-7

Acoustoelectric devices convert acoustic energy to electrical energy and vice versa. Devices working at much higher acoustic frequencies than those currently available have potential scientific and technological applications, e.g.: as detectors in ph... Read More about A high electron mobility phonotransistor.

Coherent acoustic phonons in van der Waals nanolayers and heterostructures (2018)
Journal Article
Greener, J. D., Akimov, A. V., Gusev, V., Kudrynskyi, Z., Beton, P. H., Kovalyuk, Z. D., …Patanè, A. (2018). Coherent acoustic phonons in van der Waals nanolayers and heterostructures. Physical Review B, 98(7), Article 075408. https://doi.org/10.1103/PhysRevB.98.075408

Terahertz (THz) and sub-THz coherent acoustic phonons have been successfully used as probes of various quantum systems. Since their wavelength is in the nanometer range, they can probe nanostructures buried below a surface with nanometer resolution a... Read More about Coherent acoustic phonons in van der Waals nanolayers and heterostructures.

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.

Phonon spectroscopy with chirped shear and compressive acoustic pulses (2017)
Journal Article
Poyser, C. L., York, W., Srikanthreddy, D., Glavin, B., Linnik, T., Campion, R., …Kent, A. (in press). Phonon spectroscopy with chirped shear and compressive acoustic pulses. Physical Review Letters, 119, Article 255502. https://doi.org/10.1103/PhysRevLett.119.255502

Picosecond duration compressive and shear phonon wave packets injected into (311) GaAs slabs transform after propagation through ?1??mm into chirped acoustic pulses with a frequency increasing in time due to phonon dispersion. By probing the temporal... Read More about Phonon spectroscopy with chirped shear and compressive acoustic pulses.

Molecular beam epitaxy as a growth technique for achieving free-standing zinc-blende GaN and wurtzite AlxGa1-xN (2017)
Journal Article
Novikov, S. V., Kent, A., & Foxon, C. (2017). Molecular beam epitaxy as a growth technique for achieving free-standing zinc-blende GaN and wurtzite AlxGa1-xN. Progress in Crystal Growth and Characterization of Materials, 63(2), https://doi.org/10.1016/j.pcrysgrow.2017.04.001

Currently there is a high level of interest in the development of ultraviolet (UV) light sources for solid state lighting, optical sensors, surface decontamination and water purification. III-V semiconductor UV LEDs are now successfully manufactured... Read More about Molecular beam epitaxy as a growth technique for achieving free-standing zinc-blende GaN and wurtzite AlxGa1-xN.

Piezoelectric response to coherent longitudinal and transverse acoustic phonons in a semiconductor Schottky diode (2017)
Journal Article
Srikanthreddy, D., Glavin, B., Poyser, C. L., Henini, M., Lehmann, D., Jasiukiewicz, C., …Kent, A. (in press). Piezoelectric response to coherent longitudinal and transverse acoustic phonons in a semiconductor Schottky diode. Physical Review Applied, 7(2), Article 024014. https://doi.org/10.1103/PhysRevApplied.7.024014

We study the generation of microwave electronic signals by pumping a (311) GaAs Schottky diode with compressive and shear acoustic phonons, generated by femtosecond optical excitation of an Al _lm transducer and mode conversion at the Al-GaAs interfa... Read More about Piezoelectric response to coherent longitudinal and transverse acoustic phonons in a semiconductor Schottky diode.

Heterodyne mixing of millimetre electromagnetic waves and sub-THz sound in a semiconductor device (2016)
Journal Article
Heywood, S. L., Glavin, B. A., Beardsley, R., Akimov, A. V., Carr, M. W., Norman, J., …Kent, A. J. (in press). Heterodyne mixing of millimetre electromagnetic waves and sub-THz sound in a semiconductor device. Scientific Reports, 6, Article 30396. https://doi.org/10.1038/srep30396

We demonstrate heterodyne mixing of a 94 GHz millimetre wave photonic signal, supplied by a Gunn diode oscillator, with coherent acoustic waves of frequency ~ 100 GHz, generated by pulsed laser excitation of a semiconductor surface. The mixing takes... Read More about Heterodyne mixing of millimetre electromagnetic waves and sub-THz sound in a semiconductor device.

X-ray detection with zinc-blende (cubic) GaN Schottky diodes (2016)
Journal Article
Gohil, T., Whale, J., Lioliou, G., Novikov, S. V., Foxon, C., Kent, A., & Barnett, A. (2016). X-ray detection with zinc-blende (cubic) GaN Schottky diodes. Scientific Reports, 6, Article 29535. https://doi.org/10.1038/srep29535

The room temperature X-ray responses as functions of time of two n type cubic GaN Schottky diodes (200 μm and 400 μm diameters) are reported. The current densities as functions of time for both diodes showed fast turn-on transients and increases in c... Read More about X-ray detection with zinc-blende (cubic) GaN Schottky diodes.

Nanomechanical probing of the layer/substrate interface of an exfoliated InSe sheet on sapphire (2016)
Journal Article
Beardsley, R., Akimov, A. V., Greener, J. D., Mudd, G. W., Sandeep, S., Kudrynskyi, Z. R., …Kent, A. J. (2016). Nanomechanical probing of the layer/substrate interface of an exfoliated InSe sheet on sapphire. Scientific Reports, 6, https://doi.org/10.1038/srep26970

Van der Waals (vdW) layered crystals and heterostructures have attracted substantial interest for potential applications in a wide range of emerging technologies. An important, but often overlooked, consideration in the development of implementable d... Read More about Nanomechanical probing of the layer/substrate interface of an exfoliated InSe sheet on sapphire.

Coherent acoustic phonons in colloidal semiconductor nanocrystal superlattices (2016)
Journal Article
Poyser, C. L., Czerniuk, T., Akimov, A., Diroll, B. T., Gaulding, E. A., Salasyuk, A., …Murray, C. (2016). Coherent acoustic phonons in colloidal semiconductor nanocrystal superlattices. ACS Nano, 10(1), 1163-1169. https://doi.org/10.1021/acsnano.5b06465

Coherent phonon optics in a chip with an electrically controlled active device (2015)
Journal Article
Akimov, A., Poyser, C. L., Kent, A. J., & CAMPION, R. (2015). Coherent phonon optics in a chip with an electrically controlled active device. Scientific Reports, 5, https://doi.org/10.1038/srep08279

Phonon optics concerns operations with high-frequency acoustic waves in solid media in a similar way to how traditional optics operates with the light beams (i.e. photons). Phonon optics experiments with coherent terahertz and sub-terahertz phonons p... Read More about Coherent phonon optics in a chip with an electrically controlled active device.