Mar 3, 2017
AFM imaging of large areas gets faster
The atomic force microscope (AFM) is an essential tool in nanoscience and nanotechnology. However depending on the resolution and the mode of operation, producing an image can take several tens of minutes. Recent developments have made it much faster - at the expense of the scan area size. Seeking to address this limitation, researchers from the Center of Physical Sciences and Technology in Vilnius, Lithuania, developed a rotational scanning technique for AFM, as reported in Nanotechnology.
The movie shows a 9-micrometre-pitch calibration grating imaged in real time using rotational scanning technique.
AFM allows us to produce images of the surface with extremely high - in some cases sub-atomic - resolution. It is also widely used for the evaluation of surface quality and defect inspection of nanoscale devices. However, until recently it was relatively slow due to its mechanical nature.
"Current hard drive platters are over 9cm across, spin incredibly fast and still have a bit feature size of several tens of nanometres - why don’t we try to do something similar with the AFM?" explains Artūras Ulçinas who led the research reported in Nanotechnology. To test the idea, the researchers built an experimental setup that included a 3D-printed base, a motor removed from a hard disk drive and some home-made electronics.
"The essential part of the work was developing the data reconstruction algorithm, since in such a configuration the AFM probe moves following a spiral or concentric circle trajectory and not in the usual raster fashion," says Šarūnas Vaitekonis, second author of the study. During the experiments, the sample under the probe was rotated at frequencies up to 100 Hz, with probe-surface velocities reaching more than 45 mm/s and image diameters of 142 micrometres. Even at such speeds, the features of the surface were well resolved.
On a large-area surface, getting the information or producing a modification on the nanoscale can be very expensive, both in terms of instrumentation and time. The researchers expect that as the reported technique matures it will open new possibilities in characterization of precision optical components, composite materials and semiconductor nanodevices.
Visit the Nanotechnology Focus on Scanning Probe Microscopy for more on the latest developments in atomic force microscopy and scanning tunnelling microscopy.
About the author
Artūras Ulçinas is a senior research scientist and Šarūnas Vaitekonis, is a research scientist in the Department of Nanoengineering, Center for Physical Sciences and Technology, Vilnius, Lithuania. Their interests include development and application of novel techniques and instruments for surface characterisation and patterning on the micro- and nanoscale. For more information, please visit http://www.baltfab.com and http://www.ftmc.lt.