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The Johnston Group is a research group within the sub-department of Condensed Matter Physics, which is part of the sub-faculty of Physics at the University of Oxford. Our current research may be divided into three themes (i) Semiconductor nanowires (ii) Terahertz photonic technologies and (iii) Vapour deposited Perovskite materials for photovoltaic applications.

For enquires about the group please contact:
Prof Michael B. Johnston (group leader), M.Johnston@physics.ox.ac.uk
Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, United Kingdom.

Latest Publications


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Solvent-Free Method for Defect Reduction and Improved Performance of {p-i-n} Vapor-Deposited Perovskite Solar Cells
Lohmann et al. ACS Energy Lett., 7:1903-1911 (May 2022)
[ pdf ][ DOI:10.1021/acsenergylett.2c00865 ]

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Interplay of structure, charge-carrier localization and dynamics in copper-silver-bismuth-halide semiconductors
Buizza et al. Adv. Funct. Mater., 32:2108392 (Feb 2022)
[ pdf ][ DOI:10.1002/adfm.202108392 ]

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The application of one-dimensional nanostructures in terahertz frequency devices
Peng et al. Appl. Phys. Rev., 8:041314 (Dec 2021)
[ pdf ][ DOI:10.1063/5.0060797 ]
We review the exciting field of 1D terahertz devices, with emphasis on semiconductor nanowires and carbon nanotubes

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Ultrafast photo-induced phonon hardening due to pauli blocking in $MAPbI_3$ single-crystal and polycrystalline perovskites
Xia et al. J. Phys-Mater., 4:044017 (Oct 2021)
[ pdf ][ DOI:10.1088/2515-7639/ac22b9 ]
We observed the shift of phonon modes in thin file and single crystals MAPbI3 that occurs when the materials are optically excited. We observe an ultrafast Pauli blocking effect with leads to phonon hardening / blue-shifting.

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Hot electron cooling in InSb probed by ultrafast time-resolved terahertz cyclotron resonance
Xia et al. Phys. Rev. B, 103:245205 (Jun 2021)
[ pdf ][ DOI:10.1103/PhysRevB.103.245205 ]
We develop and apply the technique of time resolved cyclotron resonance to observe electron cooling in the narrow bandgap semiconductor indium antimonide and find excellent agreement with first principles GW calculations.

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Limits to electrical mobility in lead-halide perovskite semiconductors
Xia et al. J. Phys. Chem. Lett., 12:3607-3617 (Apr 2021)
[ pdf ][ DOI:10.1021/acs.jpclett.1c00619 ]
We measure THz photoconductivity of single crystals and thin films of the prototypical metal halide perovskite MAPbI3. This direct comparison combined with DFT calculations allows us to study the influence of grain boundaries on charge-carrier scattering, and hence mobility.
Group members March 2017

News

Funded Studentship
[Nov 2022] Fully funded PhD position is available in the group for a UK/home student starting in 2023[more...]
New PhD / D.Phil Studentships
[Nov 2022] We are currently recruiting new PhD / D.Phil students [more...]