APPLICATIONS OF TECHNOLOGY:
- Atomic force microscopes (AFMs)
- High resolution atomic force and magnetic force microscopy
- Localized electrical conductivity measurements
- Biological manipulation and characterization
- Selectable aspect ratio and tip chemistry
- Ultrasharp tip
- Optimal geometry
- Electrically conducting
Alex Zettl and colleagues at Berkeley Lab have developed high quality carbon nanotube atomic force microscope (AFM) tips with a large aspect ratio, high stiffness and very sharp ends. The optimized AFM tip eliminates the need for users to go through hundreds of AFM tips to find one that is acceptable.
Rather than grow the carbon nanotube tip by chemical vapor deposition methods, the Berkeley Lab AFM tips are custom made in a transmission electron microscope (TEM) or scanning electron microscope (SEM). The mount angle and length of each tip can be adjusted to suit the intended application, e.g., super high resolution, cryogenic operation, biological samples, etc.
The Berkeley Lab tips were tested in commercial AFMs imaging biological samples such as DNA, a challenging imaging project. The images obtained were superior to those acquired using other AFM tip methods including commercially available carbon nanotube AFM tips.
The key element in accurately studying surfaces under an AFM is the AFM tip. Ideally, the tip is very sharp, making it sensitive to surface modulations at the atomic level, and long enough to probe into narrow holes or channels in the surface under study without being so long that it bends too easily or vibrates, thus compromising resolution. The properties of carbon nanotubes make them strong candidates for AFM tips. In the past, however, carbon nanotube AFM tips did not perform well because the nanotube at the tip ends was incorrectly oriented or not optimally shaped.
DEVELOPMENT STAGE: Tested in commercial AFMs and characterized by detailed TEM studies.
STATUS: Available for licensing or collaborative research.
FOR MORE INFORMATION:
Martinez, J., Yuzvinsky, T. D., Fennimore, A. M., Zettl, A., Garcia, R., Bustamante, C. “Length Control and Sharpening of Atomic Force Microscope Carbon Nanotube Tips Assisted by an Electron Beam,” Nanotechnology 16 (2005) 2493-2496.
SEE THESE OTHER BERKELEY LAB TECHNOLOGIES IN THIS FIELD:
REFERENCE NUMBER: IB-2793