Focus on Oxford Terahertz Photonics Group

My Note: I just came across this interesting webpage.
https://www-thz.physics.ox.ac.uk/

The Oxford Terahertz Photonics Group is a research group within the sub-department of Condensed Matter Physics, which is part of the sub-faculty ofPhysics at the University of Oxford. We are also a member of Oxford'sSeMicoNDuctors linkage group. We study low-energy processes in semiconductors and nanostructures on a femtosecond time-scale. Our research also involves developing novel spectroscopic techniques, for example we have recently developed a new method of terahertz time domain spectroscopy which allows the full polarisation state of terahertz pulses to be recovered. For enquires about the group please contact: Dr Michael B. Johnston (group leader), M.Johnston@physics.ox.ac.uk Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, United Kingdom.

Latest Publications Dependence of Dye Regeneration and Charge Collection on the Pore-Filling Fraction in Solid-State Dye-Sensitized Solar Cells Weisspfennig et al. Adv. Funct. Mater., 0:ASAP (Sep 2013) [ pdf ][DOI:10.1002/adfm.201301328] Direct Observation of Charge-Carrier Heating at WZ–ZB InP Nanowire Heterojunctions Yong et al. Nano Lett., 13:1 (Aug 2013) [ pdf ][ DOI:10.1021/nl402050q] We show that type II heterointerfaces in semiconductor nanowires can sustain a hot charge-carrier distribution over an extended time period. In photovoltaic applications, such heterointerfaces may hence both reduce recombination rates and limit energy losses by allowing hot-carrier harvesting Electronic properties of GaAs, InAs and InP nanowires studied by terahertz spectroscopy Joyce et al. Nanotechnology,24:214006 (May 2013) [ pdf ][ DOI:10.1088/0957-4484/24/21/214006 ] Using terahertz conductivity spectroscopy, we have assessed the ultrafast electronic properties of GaAs, InAs and InP nanowires. InAs nanowires exhibited extremely high electron mobility, highlighting their immediate suitability for high mobility devices. InP nanowires exhibited the longest carrier lifetimes, highlighting their potential for photovoltaics. Strong Carrier Lifetime Enhancement in {GaAs} Nanowires Coated with Semiconducting Polymer Yong et al. Nano Lett.,12:6293–6301 (Dec 2012) [ pdf ][ DOI:10.1021/nl3034027] We observe strong carrier lifetime enhancement for nanowires blended with semiconducting polymers. The enhancement in such inorganic-organic hybrids is found to depend crucially on the ionization potential of the polymers with respect to the Fermi energy level at the surface of the (GaAs) nanowires. Extreme sensitivity of graphene photoconductivity to environmental gases Docherty et al. Nat. Commun.,3:1228 (Nov 2012) [ pdf ][DOI:10.1038/ncomms2235 ] We show that the photoconductivity of graphene at terahertz frequencies is dramatically altered by the adsorption of atmospheric gases, such as nitrogen and oxygen. Furthermore, we observe the signature of terahertz stimulated emission from gas-adsorbed graphene. Ultra-low Surface Recombination Velocity in InP Nanowires Probed by Terahertz Spectroscopy Joyce et al. Nano Lett.,12:5325-–5330 (Oct 2012) [ pdf ][ DOI:10.1021/nl3026828] Using terahertz spectroscopy we measured long charge carrier lifetimes and a remarkably low surface recombination velocity in InP nanowires. We found that the carrier mobility is strongly limited by the presence of crystallographic defects, such as zinc-blende/wurtzite polytypism and stacking faults in these InP nanowires.