Carbon Nanotubes
- Synthesis of Carbon Nanotubes
- Raman and Fluorescence Spectroscopy
- Electrical Transport and Photo Conductivity
Carbon Nanowalls
Currently working on this project: Michael HöltigCarbon nanowalls (CNWs; sometimes also denoted as carbon nanoflowers, petals or flakes) can be described as two-dimensional graphite nanostructures with edges comprised of stacks of plane graphene sheets standing (almost) vertically on the substrate. These sheets form a wall structure with a high aspect ratio. The thickness of CNWs ranges from under one nanometer to a few tens of nanometer.
For synthesis we use a radio frequency (RF = 13.56 MHz) capacitively coupled plasma enhanced chemical vapor deposition (CC-PECVD). The central part is a vacuum reaction chamber with a fast heating stage and two electrodes for plasma generation. Several mass flow controllers are used to adjust the ratio of carbon precursor (CH4, C2H2, C2H4), etchant (H2, H2O) and auxiliary gas (Ar, He).
CNWs can be homogeneously grown by PECVD over large areas (4 cm2) at low temperatures (∼500 °C) without catalyst. Structural analysis is done by several methods, mainly SEM, Raman and conductivity measurements.
- Investigation of the growth mechanism
- Electrochemical modifications and measurements
[1] Kurita, S., A. Yoshimura, H. Kawamoto, T. Uchida, K. Kojima, M. Tachibanaa, P. Molina-Morales, and H. Nakai, Raman spectra of carbon nanowalls grown by plasma-enhanced chemical vapor deposition. Journal of Applied Physics, 2005. 97.