NachhaltigAngewandte Naturwissenschaften und WirtschaftsingenieurwesenTC Teisnach SensorikZeitschriftenartikel
M. König, Günther Ruhl, A. Gahoi, S. Wittman, T. Preis, J.-M. Batke, I. Costina, M. Lemme
Accurate Graphene-Metal Junction Characterization
IEEE Journal of the Electron Devices Society (J-EDS), vol. 7, pp. 219-226
2019
DOI: 10.1109/JEDS.2019.2891516
Abstract anzeigen
A reliable method is proposed for measuring specific contact resistivity (p C ) for graphenemetal contacts, which is based on a contact end resistance measurement. We investigate the proposed method with simulations and confirm that the sheet resistance under the metal contact (R SK ) plays an important role, as it influences the potential barrier at the graphene-metal junction. Two different complementary metal-oxide-semiconductor-compatible aluminum-based contacts are investigated to demonstrate the importance of the sheet resistance under the metal contact: the difference in R SK arises from the formation of insulating aluminum oxide (Al 2 O 3 ) and aluminum carbide (Al 4 C 3 ) interfacial layers, which depends on the graphene pretreatment and process conditions. Auger electron spectroscopy and X-ray photoelectron spectroscopy support electrical data. The method allows direct measurements of contact parameters with one contact pair and enables small test structures. It is further more reliable than the conventional transfer length method when the sheet resistance of the material under the contact is large. The proposed method is thus ideal for geometrically small contacts where it minimizes measurement errors and it can be applied in particular to study emerging devices and materials.
NachhaltigAngewandte Naturwissenschaften und WirtschaftsingenieurwesenTC Teisnach SensorikZeitschriftenartikel
Günther Ruhl, S. Wittmann, M. König, D. Neumaier
The integration of graphene into microelectronic devices
Beilstein Journal of Nanotechnology, vol. 8, pp. 1056-1064
2017
DOI: 10.3762/bjnano.8.107
Abstract anzeigen
Since 2004 the field of graphene research has attracted increasing interest worldwide. Especially the integration of graphene into microelectronic devices has the potential for numerous applications. Therefore, we summarize the current knowledge on this aspect. Surveys show that considerable progress was made in the field of graphene synthesis. However, the central issue consists of the availability of techniques suitable for production for the deposition of graphene on dielectric substrates. Besides, the encapsulation of graphene for further processing while maintaining its properties poses a challenge. Regarding the graphene/metal contact intensive research was done and recently substantial advancements were made towards contact resistances applicable for electronic devices. Generally speaking the crucial issues for graphene integration are identified today and the corresponding research tasks can be clearly defined.
NachhaltigAngewandte Naturwissenschaften und WirtschaftsingenieurwesenTC Teisnach SensorikZeitschriftenartikel
S. Vaziri, A. Smith, M. Östling, G. Lupina, J. Dabrowski, G. Lippert, W. Mehr, F. Driussi, S. Venica, V. Di Leece, A. Gnudi, M. König, Günther Ruhl, M. Belete, M. Lemme
Going ballistic: Graphene hot electron transistors
Solid State Communications, vol. 224, no. December, pp. 64-75
2015
DOI: 10.1016/j.ssc.2015.08.012
NachhaltigAngewandte Naturwissenschaften und WirtschaftsingenieurwesenTC Teisnach SensorikZeitschriftenartikel
A. Zöpfl, M.-M. Lemberger, M. König, Günther Ruhl, F.-M. Matysik, T. Hirsch
Reduced graphene oxide and graphene composite materials for improved gas sensing at low temperature
Faraday Discussions, vol. 173, pp. 403-414
2014
DOI: 10.1039/c4fd00086b
Abstract anzeigen
Reduced graphene oxide (rGO) was investigated as a material for use in chemiresistive gas sensors. The carbon nanomaterial was transferred onto a silicon wafer with interdigital gold electrodes. Spin coating turned out to be the most reliable transfer technique, resulting in consistent rGO layers of reproducible quality. Fast changes in the electrical resistance at a low operating temperature of 85 °C could be detected for the gases NO(2), CH(4) and H(2). Especially upon adsorption of NO(2) the high signal changes allowed a minimum detection of 0.3 ppm (S/N = 3). To overcome the poor selectivity, rGO was chemically functionalized with octadecylamine, or modified by doping with metal nanoparticles such as Pd and Pt, and also metal oxides such as MnO(2), and TiO(2). The different response patterns for six different materials allowed the discrimination of all of the test gases by pattern recognition based on principal component analysis.
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