Dresden 2011 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 81: Graphene: Transport

HL 81.9: Vortrag

Donnerstag, 17. März 2011, 16:45–17:00, POT 151

Graphene solution-gated field effect transistor arrays for sensing applications — •Lucas H. Hess, Pardis Ratsami, Max Seifert, Moritz Hauf, Markus Dankerl, Ian D. Sharp, Martin Stutzmann, and Jose A. Garrido — Walter Schottky Institut, Technische Universität München, Germany

Biosensing and bioelectronic applications have enormously profited from employing field effect transistors (FETs) as transducing devices, mainly due to their intrinsic amplification capability and the high integration offered by semiconductor technology. The sensitivity of so-called solution-gated FETs (SGFETs) largely depends on the charge carrier mobility and the distance between the conductive channel and the surface. On both counts, graphene appears as an ideal candidate for the development of highly sensitive SGFETs. In this work, microscopic graphene SGFET arrays are fabricated on large-scale graphene samples and characterized in aqueous environments. Both, in the electron and hole regime, the measured transconductances are significantly higher than in comparable devices based on silicon or group-III nitride transistors. The low-frequency noise of graphene SGFETs is investigated, revealing an effective gate noise of tens of µV, which compares very well with low-noise silicon devices currently used in bioelectronic applications. An on-chip structure is used for Hall-effect measurements allowing the direct determination of carrier concentrations and mobilities under electrolytic gate control. In combination with a model for the microscopic structure of water at the interface, the effect of the gate potential on charge transport in the graphene layer is analyzed.