Prof Laura Herz FRS: Publications

Charge trapping in polymer transistors probed by terahertz spectroscopy and scanning probe potentiometry

(2006)

Authors:

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

Influence of copolymer interface orientation on the optical emission of polymeric semiconductor heterojunctions

Physical Review Letters 96 (2006) 117403 4pp

Authors:

LM Herz, Sreearunothai, P, Morteani, AC, Avilov, I

Influence of mesoscopic ordering on the photoexcitation transfer dynamics in supramolecular assemblies of oligo-p-phenylenevinylene

CHEMICAL PHYSICS LETTERS 418:1-3 (2006) 196-201

Authors:

MH Chang, FJM Hoeben, P Jonkheijm, APHJ Schenning, EW Meijer, C Silva, LM Herz

Light induced recovery of polymer field effect transistors

(2006) 482-482

Authors:

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

Abstract:

We have used differential terahertz spectroscopy to monitor performance degradation in state-of-the-art polymer field effect transistors (pFETs) based on poly[(9,9-dioetylfluorene-2,7-diyl)-co-(bithiophene)] (F8T2). After extended periods of operation holes are trapped in the polymer, increasing the device's threshold voltage. We monitor the trapped charge density using THz spectroscopy, and investigate the device's recovery as trapped holes are thermally removed. Illuminating the devices for a period with above-bandgap photons leads to a change in the terahertz transmission through the device, which is short lived after switching the light off.

Polymer transistor performance monitored by terahertz spectroscopy

(2006) 203-203

Authors:

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

Abstract:

Research on polymer-based transistors is leading to the development of flexible, printable circuitry, which will be extremely cost effective to manufacture. However, the longterm performance of state-of-the-art polymer field effect transistors (pFETs) is limited by device degradation. We show that terahertz spectroscopy is an ideal tool to probe polymer device performance. Specifically we have monitored charge carrier trapping at the polymer-insulator boundary of a pFET. From these results we show that device degradation is primarily caused by a trapping of holes in the channel of the pFET, rather than by a change in hole mobility.

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