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Z4.01 - Vertical Silicon Nanogap Devices for Charge Transport Measurements on Cytochrome C 
April 23, 2014   8:30am - 8:45am

We have developed a novel vertical nanogap device (VND) structure with bare semiconductor contacts as electrodes, to investigate electronic transport phenomena in bio-electronic systems. The device fabrication starts from a Silicon-on-Insulator (SOI) substrate comprising a buried SiO2 (BOX) layer of few nm thickness, embedded within two degenerately p+-doped (boron, 0.001 - 0.005 Ωcm), single crystalline silicon layers. Individual devices were fabricated by standard photolithography and a combination of anisotropic (tetramethylammonium hydroxide, TMAH) and selective (hydrofluoric acid, HF) wet etching techniques, resulting in well-conductive silicon contacts separated by a nanogap of either 8 ± 1 nm or 4 ± 1 nm, depending on the chosen BOX thickness. For initial verification of the device electrical functionality, gold nanoparticles (diameter 15 nm) were successfully trapped onto the nanogap electrodes using AC dielectrophoresis. Subsequently, we have functionalized our silicon nanogap electrodes with Cytochrome c. This protein, which is found in many organisms as part of the electron transport chain, has already been demonstrated to sustain electronic transport even when embedded in macroscopic, dry solid-state device architectures [1]. Current-voltage measurements were performed on VNDs after protein deposition from solution, revealing a significant increase in junction conductance of typically up to 5 orders of magnitude at 2 V. Our temperature-dependent current-voltage characteristics measured from 20 K to 340 K indicated activated transport though Cytochrome c with activation energies in the range 50 -100 meV.[1] N. Amdursky, I. Pecht, M. Sheves, and D. Cahen, “Electron transport via cytochrome c on Si-H surfaces: roles of Fe and heme.,” J. Am. Chem. Soc., vol. 135, no. 16, pp. 6300-6, Apr. 2013.

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Keynote Address
Panel Discussion - Different Approaches to Commercializing Materials Research
Business Challenges to Starting a Materials-Based Company
Fred Kavli Distinguished Lectureship in Nanoscience
Application of In-situ X-ray Absorption, Emission and Powder Diffraction Studies in Nanomaterials Research - From the Design of an In-situ Experiment to Data Analysis