TY - JOUR A1 - Nick, Christoph A1 - Yadav, Sandeep A1 - Joshi, Ravi A1 - Schneider, Jörg A1 - Thielemann, Christiane T1 - A three-dimensional microelectrode array composed of vertically aligned ultra-dense carbon nanotube networks JF - Applied Physics Letters N2 - Electrodes based on carbon nanotubes are a promising approach to manufacture highly sensitive sensors with a low limit of signal detection and a high signal-to-noise ratio. This is achieved by dramatically increasing the electrochemical active surface area without increasing the overall geometrical dimensions. Typically, carbon nanotube electrodes are nearly planar and composed of randomly distributed carbon nanotube networks having a limited surface gain for a specific geometrical surface area. To overcome this limitation, we have introduced vertically aligned carbon nanotube (VACNT) networks as electrodes, which are arranged in a microelectrode pattern of 60 single electrodes. Each microelectrode features a very high aspect ratio of more than 300 and thus a dramatically increased surface area. These microelectrodes composed of VACNT networks display dramatically decreased impedance over the entire frequency range compared to planar microelectrodes caused by the enormous capacity increase. This is experimentally verified by electrochemical impedance spectroscopy and cyclic voltammetry. KW - Microelectrode arrays KW - Electrochemical impedance spectroscopy KW - Chemical compounds and components KW - Electrolytes KW - Signal processing KW - Mikroelektrode KW - Array KW - Kohlenstoff-Nanoröhre Y1 - 2015 U6 - https://doi.org/10.1063/1.4926330 VL - 2015 IS - 107 SP - 1 EP - 1 ER - TY - CHAP A1 - Yilmazoglu, Oktay A1 - Al-Daffaie, Shihab A1 - Hartnagel, Hans A1 - Joshi, Ravi A1 - Yadav, Sandeep A1 - Schneider, Jörg A1 - Nick, Christoph A1 - Thielemann, Christiane T1 - CNT photocathodes based on GaAs high-frequency photoswitches T2 - 25th International Vacuum Nanoelectronics Conference, 9 - 13 July 2012, Jeju, South Korea N2 - A high-frequency photocathode based on carbon nanotube (CNT) blocks on semiisolating GaAs or low-temperature grown GaAs was fabricated and used for electron emission in a diode configuration. The CNT blocks can achieve high currents and current densities of I=0.5 mA and J=28 mA/cm 2 at E=2.1 V/μm, respectively. The photomodulation was achieved with a GaAs photoswitch electrically connected to the bottom of the CNT block emitter. This photocathode can find applications in high frequency tubes and optically driven X-ray sources. KW - Kohlenstoff-Nanoröhre Y1 - 2012 U6 - https://doi.org/10.1109/IVNC.2012.6316840 ER - TY - JOUR A1 - Nick, Christoph A1 - Yadav, Sandeep A1 - Joshi, Ravi A1 - Schneider, Jörg A1 - Thielemann, Christiane T1 - Growth of Cortical Neurons Grown on Randomly Oriented and Vertically Aligned Dense Carbon Nanotube Networks JF - Beilstein Journal of Nanotechnology KW - Nervenzelle KW - Zellwachstum Y1 - 2014 VL - 5 SP - 1575 EP - 1579 ER -