科研之友
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摘要
The high-resolution imaging technique used in liquid environments involving dynamic mode atomic force microscopy (AFM) with a frequency modulation (FM) detection technique has been newly developed on the basis of a commercial atomic force microscopy (AFM) apparatus, which is, generally, extremely difficult because of the large decrease in Q-factor caused by hydrodynamic damping in liquids. Through various improvements and optimization, the noise density of the improved deflection sensor was 29 fm/root Hz (f(0) = 141 kHz) in liquid. In addition, the noise level and bandwidth of the FM detector were improved to 6 mHz/root Hz and 6 kHz respectively. Thermal drift was successfully regulated at less than 1 nm/min in air for a sufficiently long time without any special air conditioning treatments. As a result, we succeeded in obtaining high-resolution images of polypropylene sheet, Au thin film, and DNA structures in a buffer solution. Therefore, liquid environments are proved to be suitable for high-resolution imaging by FM-AFM under ultrahigh vacuum (UHV) condition.
- 出版日期2010-8
