Latest Publications

Generalized conductivity model for polar semiconductors at terahertz frequencies Lloyd-Hughes, Appl. Phys. Lett., 100:122103 (Mar 2012) [ pdf ][ ref ] A theoretical framework is presented that calculates the conductivity of polar semiconductors at terahertz frequencies without resorting to phenomenological fit parameters, using an expression derived from the Boltzmann transport equation. The time-dependent photoconductivity of InAs and the temperature dependent conductivity of n-doped GaAs are found experimentally by terahertz time-domain spectroscopy. The observed deviation from the Drude-Lorentz conductivity in these model systems is accounted for by this approach by including an energy-dependent electron scattering time.

Photoinduced modification of surface states in nanoporous InP Lloyd-Hughes et al., Appl. Phys. Lett., 100:132106 (Mar 2012) [ pdf ][ ref ] After photoexcitation the dark conductivity of nanoporous InP honeycombs was found to increase quasi-irreversibly. This finding was attributed to a reduction in electron depletion from surface states.

Ultrafast Dynamics of Exciton Formation in Semiconductor Nanowires Yong et al., Small, 0:0 ( 2012) [ pdf ][ ref ] The dynamics of free electron-hole pairs and excitons in GaAs–AlGaAs–GaAs core–shell–skin nanowires is investigated using femtosecond transient photoluminescence spectroscopy at 10 K.