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Compound semiconductors for terahertz photonics

(2007) 409-410

Authors:

MB Johnston, E Castro-Camus, J Lloyd-Hughes, SKE Merchant, P Parkinson, YJ Wang, LM Herz, L Fu, Q Gao, HH Tan, C Jagadish

Abstract:

Terahertz photonics is a rapidly growing field. The ultra-fast dynamics of charge carriers in semiconductors is closely linked to the performance of THz photonic devices. We study a range of ion-implanted and nano-scale semiconductors for application in novel terahertz devices.

Conductivity of nanoporous InP membranes investigated using terahertz spectroscopy

(2007) 219-220

Authors:

SKE Merchant, J Lloyd-Hughes, L Sirbu, IM Tiginyanu, P Parkinson, LM Herz, MB Johnston

Abstract:

We have investigated the conductivity of equilibrium and photoexcited electrons in nanoporous Indium phosphide (InP) of various porosities and of two orientations: (100) and (111). We observed an enhanced transmission through the nanoporous samples compared with bulk InP, resulting from a suppression of the conductivity by the pores. The frequency-dependent conductivity was extracted numerically from the transmission data. We examined the dynamical conductivity of photoexcited carriers using optical-pump THz-probe spectroscopy. After the rapid photoexcitation of electrons, the time-resolved conductivity was observed to decay slowly, with carrier recombination lifetimes exceeding 1ns for all (100)- and (111)-oriented samples.

Dimensionality-dependent energy transfer in polymer-intercalated SnS2 nanocomposites

PHYSICAL REVIEW B 75:16 (2007) ARTN 165206

Authors:

P Parkinson, E Aharon, MH Chang, C Dosche, GL Frey, A Koehler, LM Herz

Terahertz probe of carrier trapping in polymer transistors

Optica Publishing Group (2007) tua2

Authors:

J Lloyd-Hughes, T Richards, H Sirringhaus, E Castro-Camus, LM Herz, MB Johnston

Photoexcitation dynamics in thin films of insulated molecular wires

Applied Physics Letters 89:23 (2006)

Authors:

MH Chang, MJ Frampton, HL Anderson, LM Herz

Abstract:

A study is presented on how encapsulation of conjugated polymer chains affects the motion of photoexcitations and the formation of interchain aggregates in solid films. It is shown that threading of a poly(diphenylene vinylene) backbone inside insulating cyclodextrins (rotaxination) and/or complexation of the chains with poly(ethylene oxide) are effective means of preventing the diffusion of excitons to nonradiative defect sites. Ultrafast time-resolved photoluminescence data reveal that excitation transfer between encapsulated chains is still possible and, for the case of rotaxination, is likely to be facilitated through close packing of end groups belonging to adjacent chains. 漏 2006 American Institute of Physics.