Papers by Author: Anita Lloyd Spetz

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Authors: R.P. Mikalo, P. Hoffmann, D.R. Batchelor, Anita Lloyd Spetz, Ingemar Lundström, D. Schmeißer
Authors: Ruth Pearce, R. Yakimova, Jens Eriksson, L. Hultman, Mike Andersson, Anita Lloyd Spetz
Abstract: Epitaxially grown single layer graphene on silicon carbide (SiC) resistive sensors were characterised for NO2 response at room and elevated temperatures, with an n-p type transition observed with increasing NO2 concentrations for all sensors. The concentration of NO2 required to cause this transition varied with different graphene samples and is attributed to varying degrees of substrate induced Fermi-level pinning above the Dirac point. The work function of a single layer device demonstrated a steady increase in work function with increasing NO2 concentration indicating no change in reaction mechanism in the concentration range measured despite a change in sensor response direction. Epitaxially grown graphene device preparation is challenging due to poor adhesion of the graphene layer to the substrate. A field effect transistor (FET) device is presented which does not require wire bonding to contacts on graphene.
Authors: Peter Tobias, Shinji Nakagomi, A. Baranzahi, R. Zhu, Ingemar Lundström, P. Mårtensson, Anita Lloyd Spetz
Authors: Donatella Puglisi, Jens Eriksson, Mike Andersson, Joni Huotari, Manuel Bastuck, Christian Bur, Jyrki Lappalainen, Andreas Schuetze, Anita Lloyd Spetz
Abstract: Gas sensitive metal/metal-oxide field effect transistors based on silicon carbide were used to study the sensor response to benzene (C6H6) at the low parts per billion (ppb) concentration range. A combination of iridium and tungsten trioxide was used to develop the sensing layer. High sensitivity to 10 ppb C6H6 was demonstrated during several repeated measurements at a constant temperature from 180 to 300 °C. The sensor performance were studied also as a function of the electrical operating point of the device, i.e., linear, onset of saturation, and saturation mode. Measurements performed in saturation mode gave a sensor response up to 52 % higher than those performed in linear mode.
Authors: Henrik Svenningstorp, Lars Unéus, Peter Tobias, Ingemar Lundström, Lars-G. Ekedahl, Anita Lloyd Spetz
Authors: Shinji Nakagomi, Hiroaki Shinobu, Lars Unéus, Ingemar Lundström, Lars-G. Ekedahl, Rositza Yakimova, Mikael Syväjärvi, Anne Henry, Erik Janzén, Anita Lloyd Spetz
Authors: Margareta K. Linnarsson, Anita Lloyd Spetz, Martin S. Janson, Lars-G. Ekedahl, S. Karlsson, Adolf Schöner, Ingemar Lundström, Bengt Gunnar Svensson
Authors: Anita Lloyd Spetz, Lars Unéus, Henrik Svenningstorp, H. Wingbrant, Chris I. Harris, P. Salomonsson, P. Tengström, P. Mårtensson, P. Ljung, M. Mattsson, J.H. Visser, S.G. Ejakov, D. Kubinski, Lars-G. Ekedahl, Ingemar Lundström, Susan Savage
Authors: H. Wingbrant, Lars Unéus, Mike Andersson, J. Cerdà, Susan Savage, H. Svenningstorp, P. Salomonsson, P. Ljung, M. Mattsson, J.H. Visser, D. Kubinski, R. Soltis, S.G. Ejakov, D. Moldin, M. Löfdahl, M. Einehag, M. Persson, Anita Lloyd Spetz
Authors: Jens Eriksson, Donatella Puglisi, Carl Strandqvist, Rickard Gunnarsson, Sebastian Ekeroth, Ivan G. Ivanov, Ulf Helmersson, Kajsa Uvdal, Rositza Yakimova, Anita Lloyd Spetz
Abstract: Two-dimensional materials offer a unique platform for sensing where extremely high sensitivity is a priority, since even minimal chemical interaction causes noticeable changes in electrical conductivity, which can be used for the sensor readout. However, the sensitivity has to be complemented with selectivity, and, for many applications, improved response- and recovery times are needed. This has been addressed, for example, by combining graphene (for sensitivity) with metal/oxides (for selectivity) nanoparticles (NP). On the other hand, functionalization or modification of the graphene often results in poor reproducibility. In this study, we investigate the gas sensing performance of epitaxial graphene on SiC (EG/SiC) decorated with nanostructured metallic layers as well as metal-oxide nanoparticles deposited using scalable thin-film deposition techniques, like hollow-cathode pulsed plasma sputtering. It is demonstrated that under the right modification conditions the electronic properties of the surface remain those of graphene, while the surface chemistry can be tuned to improve sensitivity, selectivity and speed of response to several gases relevant for air quality monitoring and control, such as nitrogen dioxide, benzene, and formaldehyde.
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