TY - JOUR
T1 - High-mobility organic thin-film transistors based on a small-molecule semiconductor deposited in vacuum and by solution shearing
AU - Hofmockel, Robert
AU - Zschieschang, Ute
AU - Kraft, Ulrike
AU - Rödel, Reinhold
AU - Hansen, Nis Hauke
AU - Stolte, Matthias
AU - Würthner, Frank
AU - Takimiya, Kazuo
AU - Kern, Klaus
AU - Pflaum, Jens
AU - Klauk, Hagen
N1 - Funding Information:
We thank Marion Hagel at the Max Planck Institute for Solid State Research for expert technical assistance. This work was partially funded by the German Ministry of Education and Research (Project KoSiF, FKZ: 1612000463).
PY - 2013
Y1 - 2013
N2 - The small-molecule organic semiconductor 2,9-di-decyl-dinaphtho-[2,3-b: 2′,3′-f]-thieno-[3,2-b]-thiophene (C10-DNTT) was used to fabricate bottom-gate, top-contact thin-film transistors (TFTs) in which the semiconductor layer was prepared either by vacuum deposition or by solution shearing. The maximum effective charge-carrier mobility of TFTs with vacuum-deposited C10-DNTT is 8.5 cm2/V s for a nominal semiconductor thickness of 10 nm and a substrate temperature during the semiconductor deposition of 80 C. Scanning electron microscopy analysis reveals the growth of small, isolated islands that begin to coalesce into a flat conducting layer when the nominal thickness exceeds 4 nm. The morphology of the vacuum-deposited semiconductor layers is dominated by tall lamellae that are formed during the deposition, except at very high substrate temperatures. Atomic force microscopy and X-ray diffraction measurements indicate that the C 10-DNTT molecules stand approximately upright with respect to the substrate surface, both in the flat conducting layer near the surface and within the lamellae. Using the transmission line method on TFTs with channel lengths ranging from 10 to 100 μm, a relatively small contact resistance of 0.33 kΩ cm was determined. TFTs with the C10-DNTT layer prepared by solution shearing exhibit a pronounced anisotropy of the electrical performance: TFTs with the channel oriented parallel to the shearing direction have an average carrier mobility of (2.8 ± 0.3) cm2/V s, while TFTs with the channel oriented perpendicular to the shearing direction have a somewhat smaller average mobility of (1.3 ± 0.1) cm2/V s.
AB - The small-molecule organic semiconductor 2,9-di-decyl-dinaphtho-[2,3-b: 2′,3′-f]-thieno-[3,2-b]-thiophene (C10-DNTT) was used to fabricate bottom-gate, top-contact thin-film transistors (TFTs) in which the semiconductor layer was prepared either by vacuum deposition or by solution shearing. The maximum effective charge-carrier mobility of TFTs with vacuum-deposited C10-DNTT is 8.5 cm2/V s for a nominal semiconductor thickness of 10 nm and a substrate temperature during the semiconductor deposition of 80 C. Scanning electron microscopy analysis reveals the growth of small, isolated islands that begin to coalesce into a flat conducting layer when the nominal thickness exceeds 4 nm. The morphology of the vacuum-deposited semiconductor layers is dominated by tall lamellae that are formed during the deposition, except at very high substrate temperatures. Atomic force microscopy and X-ray diffraction measurements indicate that the C 10-DNTT molecules stand approximately upright with respect to the substrate surface, both in the flat conducting layer near the surface and within the lamellae. Using the transmission line method on TFTs with channel lengths ranging from 10 to 100 μm, a relatively small contact resistance of 0.33 kΩ cm was determined. TFTs with the C10-DNTT layer prepared by solution shearing exhibit a pronounced anisotropy of the electrical performance: TFTs with the channel oriented parallel to the shearing direction have an average carrier mobility of (2.8 ± 0.3) cm2/V s, while TFTs with the channel oriented perpendicular to the shearing direction have a somewhat smaller average mobility of (1.3 ± 0.1) cm2/V s.
KW - Contact resistance
KW - Organic thin-film transistors
KW - Solution shearing
KW - Thin-film morphology
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U2 - 10.1016/j.orgel.2013.09.003
DO - 10.1016/j.orgel.2013.09.003
M3 - Article
AN - SCOPUS:84885504526
VL - 14
SP - 3213
EP - 3221
JO - Organic Electronics: physics, materials, applications
JF - Organic Electronics: physics, materials, applications
SN - 1566-1199
IS - 12
ER -