Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 65: Transport Properties II (Theory)

HL 65.3: Talk

Wednesday, March 28, 2012, 17:30–17:45, ER 164

Effect of pH value and ionic strength on transport characterics of nanowire FETs — •Daijiro Nozaki, Jens Kunstmann, Felix Zörgiebel, and Gianaurelio Cuniberti — Institute for Materials Science and Max Bergmann Center of Biomaterials, TU Dresden, 01062 Dresden, Germany

For the development of ultra sensitive electrical bio/chemical sensors based on nanowires, the influence of the liquid environment such as the pH value, ionic strength of the solution, and the surface charge on the electron transport has to be understood. For this purpose, we implemented a modified Poisson-Boltzmann theory into a previously-developed multiscale model [1], which combines two models on different scales: (1) the finite element method for the calculation of electrostatic potential and (2) a Landauer transport approach based on non-equilibrium Green’s functions formalism to calculate the charge transport through the device. We investigated the changes of the electric potential and transport characteristics due to the ionic concentration, the pH value, and surface charge densities, systematically. Using this model, we could reproduce the reduction of sensitivity of the sensors due to the screening effect from the electrolyte. [1] D. Nozaki, J. Kunstmann, F. Zörgiebel, and G. Cuniberti Nanotechnology 22, 325703 (2010).