Open AccessUltrafast conductivity dynamics in pentacene probed using terahertz spectroscopy
Author(s) -
V. K. Thorsmølle,
Richard D. Averitt,
X. Chi,
David Hilton,
D. L. Smith,
A. P. Ramirez,
Antoinette J. Taylor
Publication year - 2004
Publication title -
applied physics letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 442
eISSN - 1077-3118
pISSN - 0003-6951
DOI - 10.1063/1.1644046
Subject(s) - pentacene , photoconductivity , picosecond , terahertz radiation , materials science , polaron , terahertz spectroscopy and technology , charge carrier , exciton , spectroscopy , optoelectronics , excited state , electron mobility , fluence , band gap , organic semiconductor , molecular physics , chemistry , atomic physics , condensed matter physics , optics , nanotechnology , physics , electron , thin film transistor , organic chemistry , laser , layer (electronics) , quantum mechanics , ion
We present measurements of the transient photoconductivity in pentacenesingle crystals using optical-pump THz-probe spectroscopy. We have measured thetemperature and fluence dependence of the mobility of the photoexcited chargecarriers with picosecond resolution. The pentacene crystals were excited at 3.0eV which is above the bandgap of ~2.2 eV and the induced change in thefar-infrared transmission was measured. At 30 K, the carrier mobility is mu ~0.4 cm^2/Vs and decreases to mu ~ 0.2 cm^2/Vs at room temperature. Thetransient terahertz signal reveals the presence of free carriers that aretrapped on the timescale of a few ps or less, possibly through the formation ofexcitons, small polarons, or trapping by impurities.Comment: 11 pages, 4 figures, Accepted for publication in Applied Physics Letter
Accelerating Research
Robert Robinson Avenue,
Oxford Science Park, Oxford
OX4 4GP, United Kingdom
Address
John Eccles HouseRobert Robinson Avenue,
Oxford Science Park, Oxford
OX4 4GP, United Kingdom