Regensburg 2007 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 32: C/diamond

HL 32.6: Talk

Wednesday, March 28, 2007, 17:45–18:00, H14

The interface between diamond and aqueous electrolyte — •Markus Dankerl, Andreas Reitinger, Andreas Härtl, Jose Antonio Garrido, and Martin Stutzmann — Walter Schottky Institut, Technische Universität München, Am Coulombwall 3, 85748 Garching.

C-H as well as C-O surface termination of diamond are both stable in electrolyte, but have different electrochemical characteristics. C-H terminated diamond shows the particularly interesting property of being surface conductive with holes as charge carriers. As the surface conductivity of undoped single crystalline diamond is influenced by pH, ionic strength and applied potential through the electrolyte, the design of ISFETs becomes possible. We report new results concerning the characterization of the diamond surface in contact with an aqueous electrolyte using electrochemical and electronic methods. In particular, ISFETs based on single crystalline diamond are investigated with respect to the influence of pH on the surface conductivity and the carrier concentration in the two dimensional hole gas. To this end Hall effect measurements are conducted on the conductive diamond surface in electrolyte. The screening effect of monovalent and divalent salts on the surface potential is likewise investigated. The results are discussed in the context of the influence of the parameters on the charge carriers.