Manuela Schiek - Academia.edu (original) (raw)
Papers by Manuela Schiek
MRS Proceedings, 2012
ABSTRACT Thin films (50 nm) of 2,5-di-4-biphenylthiophene (PPTPP), 5,5´-di-4-biphenylyl-2,2´-bith... more ABSTRACT Thin films (50 nm) of 2,5-di-4-biphenylthiophene (PPTPP), 5,5´-di-4-biphenylyl-2,2´-bithiophene (PPTTPP) and 4,4´-di-2,2´-bithienylbiphenyl (TTPPTT) were vapor-deposited on microstructured gold (source- and drain-) electrode arrays on thermal SiO2 as gate dielectric with underlying Si serving as gate electrode. The films were studied in their field-effect characteristics during film growth and subsequent to it. A decay of specific conductivity and of charge carrier mobility was observed in subsequent measurements. During annealing without an applied field the films recovered but showed a second decay as soon as an electric field was applied again for repeated characterization. Induced dipoles and subsequent structural changes as well as chemical interactions with the SiO2 interface are discussed as possible origins of these observations.
Advanced Fabrication Technologies for Micro/Nano Optics and Photonics, 2008
Aligned ensembles of nanoscopic nanofibers from organic molecules such as para-phenylenes for pho... more Aligned ensembles of nanoscopic nanofibers from organic molecules such as para-phenylenes for photonic applications can be fabricated by self-assembled molecular growth on a suited dielectric substrate. Epitaxy together with alignment due to electric surface fields determines the growth directions. In this paper we demonstrate how aligned growth along arbitrary directions can be realized by depositing the molecules on a micro-structured and gold covered Silicon surface, consisting of channels and ridges. For the correct combination of ridge width and deposition temperature fibers grow perpendicular to the ridge edge, emitting light polarized along the ridges after UV excitation.
Organic Photonic Materials and Devices XVI, 2014
ABSTRACT Functionalization of small, rod like organic molecules can be used to optimize organic d... more ABSTRACT Functionalization of small, rod like organic molecules can be used to optimize organic devices. Here we report on nanofiber formation and thin film growth of a methoxy-functionalized para-quaterphenylene (1,4'''-Dimethoxy- 4,1':4',1'':4'',1'''-quaterphenylene, MOP4) on prototypical dielectric substrates such as muscovite mica, phlogopite mica, highly ordered pyrolytic graphite (HOPG), and on the alkali halide NaCl. The nanofibers consist of lying molecules, the films of upright standing ones. The grown samples are characterized by polarized optical microscopy (fluorescence, birefringence, bireflectance), by atomic force microscopy (AFM), and by Kelvin probe force microscopy (KPFM) to gain insight into their structure and epitaxial relation with the substrates.
Springer Proceedings in Physics, 2009
The growth of 2,5-Di-4-biphenyl-thiophene (PPTPP) on the dielectric substrates NaCl, KCl, KAP, mu... more The growth of 2,5-Di-4-biphenyl-thiophene (PPTPP) on the dielectric substrates NaCl, KCl, KAP, muscovite mica, and phlogopite mica is investigated by atomic force microscopy (AFM) and fluorescence microscopy. In all cases fibers are formed with several ten nanometers height and several hundred nanometers width, respectively. Only for PPTPP on muscovite mica the fibers are mutually parallel aligned along a single substrate
Small (Weinheim an der Bergstrasse, Germany), 2008
A new route to bottom-up organic nanotechnology is presented. Molecular building blocks with spec... more A new route to bottom-up organic nanotechnology is presented. Molecular building blocks with specific optoelectronic properties are designed and grown via directed self-assembly arrays of morphologically controlled light-emitting organic nanofibers on template surfaces. The fibers can be easily transferred from the growth substrate to device platforms either as single entities or as ordered arrays. Due to the extraordinary flexibility in the design of their optoelectronic properties they serve as key elements in next-generation nanophotonic devices.
Integrated Optics: Devices, Materials, and Technologies XI, 2007
Nanofibers from symmetrically and unsymmetrically functionalized p-quaterphenylenes are fabricate... more Nanofibers from symmetrically and unsymmetrically functionalized p-quaterphenylenes are fabricated by a bottom-up process on muscovite mica. The symmetrically functionalized p-quaterphenylenes emit intense, polarized blue light after unpolarized UV-excitation. Upon implementing electron push-pull functional groups like chlor and methoxy groups to the molecular building block new properties of the nanoaggregates have been generated: the nanofibers exhibit increased non-linear optical properties, acting,
MRS Proceedings, 2012
ABSTRACT Thin films (50 nm) of 2,5-di-4-biphenylthiophene (PPTPP), 5,5´-di-4-biphenylyl-2,2´-bith... more ABSTRACT Thin films (50 nm) of 2,5-di-4-biphenylthiophene (PPTPP), 5,5´-di-4-biphenylyl-2,2´-bithiophene (PPTTPP) and 4,4´-di-2,2´-bithienylbiphenyl (TTPPTT) were vapor-deposited on microstructured gold (source- and drain-) electrode arrays on thermal SiO2 as gate dielectric with underlying Si serving as gate electrode. The films were studied in their field-effect characteristics during film growth and subsequent to it. A decay of specific conductivity and of charge carrier mobility was observed in subsequent measurements. During annealing without an applied field the films recovered but showed a second decay as soon as an electric field was applied again for repeated characterization. Induced dipoles and subsequent structural changes as well as chemical interactions with the SiO2 interface are discussed as possible origins of these observations.
Advanced Fabrication Technologies for Micro/Nano Optics and Photonics, 2008
Aligned ensembles of nanoscopic nanofibers from organic molecules such as para-phenylenes for pho... more Aligned ensembles of nanoscopic nanofibers from organic molecules such as para-phenylenes for photonic applications can be fabricated by self-assembled molecular growth on a suited dielectric substrate. Epitaxy together with alignment due to electric surface fields determines the growth directions. In this paper we demonstrate how aligned growth along arbitrary directions can be realized by depositing the molecules on a micro-structured and gold covered Silicon surface, consisting of channels and ridges. For the correct combination of ridge width and deposition temperature fibers grow perpendicular to the ridge edge, emitting light polarized along the ridges after UV excitation.
Organic Photonic Materials and Devices XVI, 2014
ABSTRACT Functionalization of small, rod like organic molecules can be used to optimize organic d... more ABSTRACT Functionalization of small, rod like organic molecules can be used to optimize organic devices. Here we report on nanofiber formation and thin film growth of a methoxy-functionalized para-quaterphenylene (1,4'''-Dimethoxy- 4,1':4',1'':4'',1'''-quaterphenylene, MOP4) on prototypical dielectric substrates such as muscovite mica, phlogopite mica, highly ordered pyrolytic graphite (HOPG), and on the alkali halide NaCl. The nanofibers consist of lying molecules, the films of upright standing ones. The grown samples are characterized by polarized optical microscopy (fluorescence, birefringence, bireflectance), by atomic force microscopy (AFM), and by Kelvin probe force microscopy (KPFM) to gain insight into their structure and epitaxial relation with the substrates.
Springer Proceedings in Physics, 2009
The growth of 2,5-Di-4-biphenyl-thiophene (PPTPP) on the dielectric substrates NaCl, KCl, KAP, mu... more The growth of 2,5-Di-4-biphenyl-thiophene (PPTPP) on the dielectric substrates NaCl, KCl, KAP, muscovite mica, and phlogopite mica is investigated by atomic force microscopy (AFM) and fluorescence microscopy. In all cases fibers are formed with several ten nanometers height and several hundred nanometers width, respectively. Only for PPTPP on muscovite mica the fibers are mutually parallel aligned along a single substrate
Small (Weinheim an der Bergstrasse, Germany), 2008
A new route to bottom-up organic nanotechnology is presented. Molecular building blocks with spec... more A new route to bottom-up organic nanotechnology is presented. Molecular building blocks with specific optoelectronic properties are designed and grown via directed self-assembly arrays of morphologically controlled light-emitting organic nanofibers on template surfaces. The fibers can be easily transferred from the growth substrate to device platforms either as single entities or as ordered arrays. Due to the extraordinary flexibility in the design of their optoelectronic properties they serve as key elements in next-generation nanophotonic devices.
Integrated Optics: Devices, Materials, and Technologies XI, 2007
Nanofibers from symmetrically and unsymmetrically functionalized p-quaterphenylenes are fabricate... more Nanofibers from symmetrically and unsymmetrically functionalized p-quaterphenylenes are fabricated by a bottom-up process on muscovite mica. The symmetrically functionalized p-quaterphenylenes emit intense, polarized blue light after unpolarized UV-excitation. Upon implementing electron push-pull functional groups like chlor and methoxy groups to the molecular building block new properties of the nanoaggregates have been generated: the nanofibers exhibit increased non-linear optical properties, acting,