Operation of astigmatic-detection atomic force microscopy in liquid environments
Journal
Review of Scientific Instruments
Journal Volume
84
Journal Issue
10
Date Issued
2013
Author(s)
Liao, H.-S.
Huang, K.-Y.
Hwang, I.-S.
Chang, T.-J.
Hsiao, W.W.
Lin, H.-H.
Hwu, E.-T.
Abstract
The astigmatic detection system (ADS) based on commercial optical pickup head was demonstrated to achieve a sub-nanometer sensitivity in detecting the vertical movement of an object surface in air. The detection laser spot of the ADS was sub-μm and the detection bandwidth was over 80 MHz. These advantages allow detection of high-frequency mechanical resonance of very small objects, which would have many important applications in nanotechnology. In this work, we optimized the operation conditions of ADS to achieve good sensitivity in aqueous solutions. We demonstrated good contrast and good spatial resolution of cancer cells in water with the optical profilometry mode. We also built an ADS-AFM (atomic force microscopy) for imaging in water. A novel cantilever holder was designed, and the spurious peaks were suppressed down to 26.0% of the real resonance peak. Most importantly, we demonstrated that the ADS-AFM could resolve single atomic steps on a graphite substrate and image soft DNA molecules on mica in water. ? 2013 AIP Publishing LLC.
Other Subjects
Graphite substrate; High frequency HF; Liquid environment; Mechanical resonance; Operation conditions; Optical pickup heads; Optical profilometry; Spatial resolution; Deceleration; Mica; Optical data processing; Atomic force microscopy; aluminum silicate; DNA; graphite; mica; water; article; atomic force microscopy; chemistry; light related phenomena; methodology; surface property; Aluminum Silicates; DNA; Graphite; Microscopy, Atomic Force; Optical Processes; Surface Properties; Water
Type
journal article