Microdiffraction imaging—a suitable tool to characterize organic electronic devices

Clemens Liewald; Simon Noever; Stefan Fischer; Janina Roemer; Tobias U. Schülli; Bert Nickel; Clemens Liewald; Simon Noever; Stefan Fischer; Janina Roemer; Tobias U. Schülli; Bert Nickel

doi:10.3934/matersci.2015.4.369

AIMS Materials Science

2015, Volume 2, Issue 4: 369-378. doi: 10.3934/matersci.2015.4.369

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Microdiffraction imaging—a suitable tool to characterize organic electronic devices

1.
Fakultät für Physik & Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Geschwister-Scholl-Platz 1, 80539 Munich, Germany;
2.
Nanosystems Initiative Munich, Schellingstrasse 4, 80799 Munich, Germany;
3.
ID01/ESRF, 71 avenue des Martyrs, CS 40220, F-38043 Grenoble Cedex 9, France

Received: 12 June 2015 Accepted: 27 September 2015 Published: 12 October 2015

Tailoring device architecture and active film morphology is crucial for improving organic electronic devices. Therefore, knowledge about the local degree of crystallinity is indispensable to gain full control over device behavior and performance. In this article, we report on microdiffraction imaging as a new tool to characterize organic thin films on the sub-micron length scale. With this technique, which was developed at the ID01 beamline at the ESRF in Grenoble, a focused X-ray beam (300 nm diameter, 12.5 keV energy) is scanned over a sample. The beam size guarantees high resolution, while material and structure specificity is gained by the choice of Bragg condition.
Here, we explore the possibilities of microdiffraction imaging on two different types of samples. First, we measure the crystallinity of a pentacene thin film, which is partially buried beneath thermally deposited gold electrodes and a second organic film of fullerene C₆₀. The data shows that the pentacene film structure is not impaired by the subsequent deposition and illustrates the potential of the technique to characterize artificial structures within fully functional electronic devices. Second, we investigate the local distribution of intrinsic polymorphism of pentacene thin films, which is very likely to have a substantial influence on electronic properties of organic electronic devices. An area of 40 μm by 40 μm is scanned under the Bragg conditions of the thin-film phase and the bulk phase of pentacene, respectively. To find a good compromise between beam footprint and signal intensity, third order Bragg condition is chosen. The scans show complementary signal distribution and hence demonstrate details of the crystalline structure with a lateral resolution defined by the beam footprint (300 nm by 3 μm).
The findings highlight the range of applications of microdiffraction imaging in organic electronics, especially for organic field effect transistors and for organic solar cells.
- focused X-ray,
- polymorphism,
- multilayer,
- morphology,
- scanning X-ray diffraction microscopy,
- synchrotron
Citation: Clemens Liewald, Simon Noever, Stefan Fischer, Janina Roemer, Tobias U. Schülli, Bert Nickel. Microdiffraction imaging—a suitable tool to characterize organic electronic devices[J]. AIMS Materials Science, 2015, 2(4): 369-378. doi: 10.3934/matersci.2015.4.369

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Abstract

Tailoring device architecture and active film morphology is crucial for improving organic electronic devices. Therefore, knowledge about the local degree of crystallinity is indispensable to gain full control over device behavior and performance. In this article, we report on microdiffraction imaging as a new tool to characterize organic thin films on the sub-micron length scale. With this technique, which was developed at the ID01 beamline at the ESRF in Grenoble, a focused X-ray beam (300 nm diameter, 12.5 keV energy) is scanned over a sample. The beam size guarantees high resolution, while material and structure specificity is gained by the choice of Bragg condition.
Here, we explore the possibilities of microdiffraction imaging on two different types of samples. First, we measure the crystallinity of a pentacene thin film, which is partially buried beneath thermally deposited gold electrodes and a second organic film of fullerene C₆₀. The data shows that the pentacene film structure is not impaired by the subsequent deposition and illustrates the potential of the technique to characterize artificial structures within fully functional electronic devices. Second, we investigate the local distribution of intrinsic polymorphism of pentacene thin films, which is very likely to have a substantial influence on electronic properties of organic electronic devices. An area of 40 μm by 40 μm is scanned under the Bragg conditions of the thin-film phase and the bulk phase of pentacene, respectively. To find a good compromise between beam footprint and signal intensity, third order Bragg condition is chosen. The scans show complementary signal distribution and hence demonstrate details of the crystalline structure with a lateral resolution defined by the beam footprint (300 nm by 3 μm).
The findings highlight the range of applications of microdiffraction imaging in organic electronics, especially for organic field effect transistors and for organic solar cells.

References

[1]	Bredas JL, Beljonne D, Coropceanu V, et al. (2004) Charge-transfer and energy-transfer processes in pi-conjugated oligomers and polymers: A molecular picture. Chem Rev 104: 4971-5003. doi: 10.1021/cr040084k
[2]	He T, Stolte M, Burschka C, et al. (2015) Single-crystal field-effect transistors of new Cl2-NDI polymorph processed by sublimation in air. Nat Commun 6: 5954. doi: 10.1038/ncomms6954
[3]	Tang Q, Zhang DQ, Wang SL, et al. (2009) A Meaningful Analogue of Pentacene: Charge Transport, Polymorphs, and Electronic Structures of Dihydrodiazapentacene. Chem Mater 21: 1400-1405. doi: 10.1021/cm9001916
[4]	Schiefer S, Huth M, Dobrinevski A, et al. (2007) Determination of the crystal structure of substrate-induced pentacene polymorphs in fiber structured thin films. J Am Chem Soc 129: 10316-10317. doi: 10.1021/ja0730516
[5]	Mattheus CC, Dros AB, Baas J, et al. (2003) Identification of polymorphs of pentacene. Synth Met 138: 475-481. doi: 10.1016/S0379-6779(02)00467-8
[6]	Westermeier C, Cernescu A, Amarie S, et al. (2014) Sub-micron phase coexistence in small-molecule organic thin films revealed by infrared nano-imaging. Nat Commun 5: 5101. doi: 10.1038/ncomms6101
[7]	Durr AC, Schreiber F, Kelsch M, et al. (2002) Morphology and thermal stability of metal contacts on crystalline organic thin films. Adv Mater 14: 961-963. doi: 10.1002/1521-4095(20020705)14:13/14<961::AID-ADMA961>3.0.CO;2-X
[8]	Kahn A, Koch N, Gao WY (2003) Electronic structure and electrical properties of interfaces between metals and pi-conjugated molecular films. J Polym Sci Part B Polym Phys 41: 2529-2548. doi: 10.1002/polb.10642
[9]	Necliudov PV, Shur MS, Gundlach DJ, et al. (2003) Contact resistance extraction in pentacene thin film transistors. Solid State Electron 47: 259-262. doi: 10.1016/S0038-1101(02)00204-6
[10]	Klauk H, (2006) Organic Electronics: Materials, Manufacturing, and Applications, 1 Eds., Wiley-VCH.
[11]	Dam HF, Andersen TR, Pedersen EBL, et al. (2015) Enabling flexible polymer tandem solar cells by 3D ptychographic imaging. Adv Energy Mater 5: 1400736.
[12]	Fuller T, Banhart F (1996) In situ observation of the formation and stability of single fullerene molecules under electron irradiation. Chem Phys Lett 254: 372-378. doi: 10.1016/0009-2614(96)00338-7
[13]	Tolan M, (2013) X-Ray Scattering from Soft-Matter Thin Films: Materials Science and Basic Research, Springer.
[14]	Fritz SE, Martin SM, Frisbie CD, et al. (2004) Structural characterization of a pentacene monolayer on an amorphous SiO2 substrate with grazing incidence X-ray diffraction. J Am Chem Soc 126: 4084-4085. doi: 10.1021/ja049726b
[15]	Noever SJ, Fischer S, Nickel B (2013) Dual Channel Operation Upon n-Channel Percolation in a Pentacene-C60 Ambipolar Organic Thin Film Transistor. Adv Mater 25: 2147-2151. doi: 10.1002/adma.201203964
[16]	Qazilbash MM, Tripathi A, Schafgans AA, et al. (2011) Nanoscale imaging of the electronic and structural transitions in vanadium dioxide. Phys Rev B 83: 165108. doi: 10.1103/PhysRevB.83.165108
[17]	Chahine GA, Richard MI, Homs-Regojo RA, et al. (2014) Imaging of strain and lattice orientation by quick scanning X-ray microscopy combined with three-dimensional reciprocal space mapping. J Appl Crystallogr 47: 762-769. doi: 10.1107/S1600576714004506
[18]	Chahine GA, Zoellner MH, Richard M-I, et al. (2015) Strain and lattice orientation distribution in SiN/Ge complementary metal-oxide-semiconductor compatible light emitting microstructures by quick x-ray nano-diffraction microscopy. Appl Phys Lett 106: 071902. doi: 10.1063/1.4909529
[19]	Zoellner MH, Richard M-I, Chahine GA, et al. (2015) Imaging Structure and Composition Homogeneity of 300 mm SiGe Virtual Substrates for Advanced CMOS Applications by Scanning X-ray Diffraction Microscopy. ACS Appl Mater Interfaces 7: 9031-9037. doi: 10.1021/am508968b
[20]	Paci B, Bailo D, Albertini VR, et al. (2013) Spatially-resolved in-situ structural study of organic electronic devices with nanoscale resolution: the plasmonic photovoltaic case study. Adv Mater 25: 4760-4765. doi: 10.1002/adma.201301682
[21]	Reich C, Hochrein MB, Krause B, et al. (2005) A microfluidic setup for studies of solid-liquid interfaces using x-ray reflectivity and fluorescence microscopy. Rev Sci Instrum 76.
[22]	Dimitrakopoulos CD, Brown AR, Pomp A (1996) Molecular beam deposited thin films of pentacene for organic field effect transistor applications. J Appl Phys 80: 2501-2508. doi: 10.1063/1.363032
[23]	Knipp D, Street RA, Volkel A, et al. (2003) Pentacene thin film transistors on inorganic dielectrics: Morphology, structural properties, and electronic transport. J Appl Phys 93: 347-355. doi: 10.1063/1.1525068
[24]	Yanagisawa H, Tamaki T, Nakamura M, et al. (2004) Structural and electrical characterization of pentacene films on SiO₂ grown by molecular beam deposition. Thin Solid Films 464: 398-402.
[25]	Seeck OH, Deiter C, Pflaum K, et al. (2012) The high-resolution diffraction beamline P08 at PETRA III. J Synchrotron Radiat 19: 30-38. doi: 10.1107/S0909049511047236
[26]	Ponchut C, Rigal JM, Clément J, et al. (2011) MAXIPIX, a fast readout photon-counting X-ray area detector for synchrotron applications. J Instrum 6: C01069.
[27]	Kaefer D, Ruppel L, Witte G (2007) Growth of pentacene on clean and modified gold surfaces. Phys Rev B 75.
[28]	Bouchoms IPM, Schoonveld WA, Vrijmoeth J, et al. (1999) Morphology identification of the thin film phases of vacuum evaporated pentacene on SiO₂ substrates. Synth Met 104: 175-178. doi: 10.1016/S0379-6779(99)00050-8
[29]	Govyadinov AA, Mastel S, Golmar F, et al. (2014) Recovery of Permittivity and Depth from Near-Field Data as a Step toward Infrared Nanotomography. ACS Nano 8: 6911-6921. doi: 10.1021/nn5016314
[30]	Seiki N, Shoji Y, Kajitani T, et al. (2015) Rational synthesis of organic thin films with exceptional long-range structural integrity. Science 348: 1122-1126. doi: 10.1126/science.aab1391
[31]	Collins BA, Cochran JE, Yan H, et al. (2012) Polarized X-ray scattering reveals non-crystalline orientational ordering in organic films. Nat Mater 11: 536-543. doi: 10.1038/nmat3310
[32]	Hub C, Burkhardt M, Halik M, et al. (2010) In situ STXM investigations of pentacene-based OFETs during operation. J Mater Chem 20: 4884-4887. doi: 10.1039/c0jm00423e
[33]	Weickert J, Dunbar RB, Hesse HC, et al. (2011) Nanostructured Organic and Hybrid Solar Cells. Adv Mater 23: 1810-1828. doi: 10.1002/adma.201003991
[34]	Westermeier C, Fiebig M, Nickel B (2013) Mapping of trap densities and hotspots in pentacene thin-film transistors by frequency-resolved scanning photoresponse microscopy. Adv Mater 25: 5719-5724. doi: 10.1002/adma.201300958

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