58 research outputs found
Space Charge Limited Transport and Time of Flight Measurements in Tetracene Single Crystals: a Comparative Study
We report on a systematic study of electronic transport in tetracene single
crystals by means of space charge limited current spectroscopy and time of
flight measurements. Both - and time of flight measurements show that the
room-temperature effective hole-mobility reaches values close to
cm/Vs and show that, within a range of temperatures, the mobility increases
with decreasing temperature. The experimental results further allow the
characterization of different aspects of the tetracene crystals. In particular,
the effects of both deep and shallow traps are clearly visible and can be used
to estimate their densities and characteristic energies. The results presented
in this paper show that the combination of - measurements and time of
flight spectroscopy is very effective in characterizing several different
aspects of electronic transport through organic crystals.Comment: Accepted by J. Appl. Phys.; tentatively scheduled for publication in
the January 15, 2004 issue; minor revisions compared to previous cond-mat
versio
Effect of Impurities on Pentacene Thin Film Growth for Field-Effect Transistors
Pentacenequinone (PnQ) impurities have been introduced into a pentacene
source material at number densities from 0.001 to 0.474 to quantify the
relative effects of impurity content and grain boundary structure on transport
in pentacene thin-film transistors. Atomic force microscopy (AFM) and
electrical measurements of top-contact pentacene thin-film transistors have
been employed to directly correlate initial structure and final film
structures, with the device mobility as a function of added impurity content.
The results reveal a factor four decrease in mobility without significant
changes in film morphology for source PnQ number fractions below ~0.008. For
these low concentrations, the impurity thus directly influences transport,
either as homogeneously distributed defects or by concentration at the
otherwise-unchanged grain boundaries. For larger impurity concentrations, the
continuing strong decrease in mobility is correlated with decreasing grain
size, indicating an impurity-induced increase in the nucleation of grains
during early stages of film growth.Comment: 18 pages, 4 Figures, 1 Tabl
Measurements of sulfur compounds in CO2 by diode laser atomic absorption spectrometry
International audienc
Aspects of the Charge Carrier Transport in Highly-Ordered Crystals of Polyaromatic Molecules
Impact broadening and shift rates for the 6p
The collisional broadening and shift rate coefficients of the 283.39 nm
, 364.06 nm
, 368.45 nm
and 405.90 nm
Pb lines by He and Ar have been measured by
fitting the experimental absorption line shapes to theoretical Voigt profiles. The
absorption measurements were performed in a resistively heated, Pb loaded oven with an
integrated dc noble gas discharge to produce also Pb atoms in the
and
metastable states. The diffusion of the
metastable atoms out of the discharge zone into the neutral noble-gas atmosphere enabled
the line-shape and shift measurement of the lines involving the metastable states
without the influence of the discharge plasma
Temperature Measurement of Liquids by Differential Absorption of Two Diode Lasers: Application of Contactless Optical Detection in Isotachophoresis
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