Dresden 2014 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 108: Poster: Ultra-fast phenomena / Optical properties / Semiconductor laser / Devices and device concepts

HL 108.28: Poster

Donnerstag, 3. April 2014, 17:00–20:00, P1

ZnO-based inverter as biosensors — •Agnes Holtz, Fabian Klüpfel, Holger von Wenckstern, and Marius Grundmann — Universität Leipzig, Fakultät für Physik und Geowissenschaften, Abteilung Halbleiterphysik, Linnéstr. 5, 04103 Leipzig

Transparent semiconducting oxides find application as switching transistor within active-matrix displays. Another interesting field of application is the integration of such transistors within multi electrode biosensor arrays. These can be used to measure the change of membrane potential of externally stimulated nerve cells cultivated on the transparent amplifier. This would permit to synchronously study the nerve cells visually and electrically providing means to establish connections between the arrangement of cells and their "communication" behavior. The inverter amplifies the cell signals directly at the measurement electrodes. This might result in a higher signal-to-noise ratio due to the short path between electrode and amplifier. The ZnO layer was deposited by pulsed-laser deposition on a-plane sapphire substrate. We compared inverters comprising field effect transistors with different gate materials such as Au, PtO_x or ZnCo₂O₄. The epoxy based photo resist SU 8 was used to encapsulate the chip against the elektrolyte. The inverters were characterized electrically by IU and frequency dependent measurements at room temperature. The maximal slope we measure is 80. We use simple inverters consisting of two transistors because of the high amplification and the low space requirements. To ensure measuring at the point of highest amplification of the inverter characteristics an external amplifier circuit was developed.