Berlin 2005 – scientific programme

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HL: Halbleiterphysik

HL 51: GaN: Pr
äparation und Charakterisierung III

HL 51.1: Talk

Tuesday, March 8, 2005, 10:45–11:00, TU P-N202

Functionalization of Group III-Nitride Surfaces for Biosensor Applications — •Barbara Baur, Georg Steinhoff, Thomas Wassner, Martin Stutzmann, and Martin Eickhoff — Walter Schottky Institut, Technische Universität München, D-85748 Garching

Group III-nitrides are promising substrate materials for biophysical applications as they combine excellent electronic characteristics with biocompatibility and long term stability in liquid electrolytes. In particular, AlGaN/GaN electrolyte gate field effect transistors (EGFETs) have a great potential as sensor devices for electronic detection of biochemical processes, such as the recently demonstrated recording of cell signals. As a critical issue in the development of AlGaN-based biochemical transducers, the design and the analysis of inorganic/organic interface are adressed in this contribution.

We have studied the covalent functionalization of AlGaN-surfaces by deposition of self assembled layers (SAMs) of two different kinds of silane molecules. The deposition of octadecyltrimethoxysilane (ODTMS) resulted in hydrophobic AlN- and GaN-surfaces. For immobilization of DNA on AlGaN-surfaces the formation of SAMs of aminopropyltriethoxysilane (APTES) was studied. The functionalized surfaces were investigated by atomic force microscopy, X-ray photoelectron spectroscopy, X-ray reflectivity, thermal desorption and fluorescence microscopy. The detection of DNA hybridization with complementary sequences immobilized on GaN surfaces by fluorescence microscopy will be presented and the label free electronic detection of DNA with AlGaN-based devices is discussed.