Berlin 2015 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 61: Posters III (Organic-inorganic perovskite semiconductors; Organic photovoltaics and electronics; Photovoltaics; Energy science; New materials and concepts)

HL 61.20: Poster

Mittwoch, 18. März 2015, 15:00–20:00, Poster F

Band-like electron transport and high mobility in F₂-TCNQ single-crystal field-effect transistors — •Yulia Krupskaya¹, Marco Gibertini², Nicola Marzari², and Alberto Morpurgo¹ — ¹University of Geneva, Geneva, Switzerland — ²EPFL, Lausanne, Switzerland

It is believed that in organic single-crystal field-effect transistors (FET) of the highest quality, the electron transport occurs in the band-like regime, with the carrier mobility increasing upon lowering temperature. Neither the microscopic nature of this regime, nor why it occurs only in some materials but not in others is currently well understood. To address these issues, we performed a study of electron transport in single-crystal FET of different tetracyanoquinodimethane (F_x-TCNQ) molecules. We show that F₂-TCNQ devices exhibit the most pronounced band-like transport observed to date (a room-temperature electron mobility µ = 6-7 cm²/Vs, increasing up to 25 cm²/Vs at 150 K), whereas in TCNQ and F₄-TCNQ FET µ = 0.1-0.2 cm²/Vs at room temperature and decreases upon cooling. Moreover, we present a comparative analysis of the crystal structure, electronic structure and the electron-phonon interactions for the three studied materials aimed on understanding of the microscopic mechanisms responsible for so different thransport properties.

Financial support: DFG KR 4364/1-1