Berlin 2018 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 18: Optical Analysis of Thin Films (Reflection, Ellipsometry, Raman, IR-DUV Spectroscopy, ...): Session I
DS 18.2: Vortrag
Mittwoch, 14. März 2018, 10:15–10:30, H 0111
Investigation on the electric-field-induced switching effect of copper-tetrathianoquinodimethane by polarized Raman spectroscopy — •Yanlong Xing1, Eugen Speiser1, Petra S. Dittrich2, and Norbert Esser1 — 1Leibniz-Institut für Analytische Wissenschaften - ISAS - e. V, 12489 Berlin, Germany — 2Department of Biosystems Science and Engineering, ETH Zurich, CH-4058, Basel, Switzerland
Copper-tetrathianoquinodimethane (Cu-TCNQ) is a kind of important material due to its electric-field-induced reversible switching characteristics in conductivity. However, there is still inconsistency in reported studies regarding the switching effect: one proposed mechanism is the phase/composition changes (from phase II to phase I or between charged and neutral TCNQ molecules); the other mechanism is the Schottky contact between Al electrodes and Cu-TCNQ. To clarify this issue, we performed polarized Raman measurement on Cu-TCNQ crystals upon applying electric field by using a microdevice with Pt electrodes.
The rotational polarized Raman spectra showed the different crytal structures of the two phases of Cu-TCNQ (I and II). When applying an electric field to Cu-TCNQ wire (phase I), only after a threshold voltage, electron transfer between TCNQ0 and TCNQ- could be observed by the Raman signal of TCNQ0. A quantitative study on the Raman intensity and conductivity of Cu-TCNQ was under investigation, as well as the crystal structure changes of Cu-TCNQ.