Regensburg 2010 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 16: Diamond

HL 16.5: Vortrag

Montag, 22. März 2010, 17:00–17:15, H13

Noise characterization of diamond solution gate field effect transistors for biosensing applications — •Moritz Hauf, Lucas Hess, Martin Stutzmann, and José A. Garrido — Walter Schottky Institut, Technische Universität München, 85748 Garching, Germany

Diamond, when terminated with hydrogen at the surface, shows the intriguing property of a p-type surface conductivity with a two-dimensional hole gas forming beneath the surface. If brought into electrolyte solutions, this surface conductivity can be effectively modulated by an electrode controlling the electrolyte potential. This allows for the fabrication of FETs with the electrolyte solution functioning as the gate, therefore called solution gate FETs. SGFETs show great potential for biosensing and biomedical applications due to the operation in aqueous environment. In particular, diamond is considered a suitable material due to its good biocompatibility and electrochemical inertness.

We have shown that such diamond SGFETs are capable of extracellular recording of action potentials from different cell types. For future applications, it will be highly important to have a low noise level of the SGFET for the chemical detection of single neurotransmitter vesicles. For comparison of device performance we report on the noise of SGFETs realized with different substrate materials such as diamond, graphene, Si, and GaN. For diamond, we compare different surface properties such as surface roughness or dislocation density of the diamond crystal that can contribute to the noise level.