1999 Fiscal Year Final Research Report Summary
Atomic Force Spectroscopy using a force balance technique
| Project/Area Number |
09650066
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied physics, general
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| Research Institution | Osaka Prefecture University |
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Principal Investigator |
KIKUTA Hisao Osaka Prefecture University, College of Engineering, Research Associate, 工学部, 助手 (10214743)
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| Project Period (FY) |
1997 – 1999
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| Keywords | Atomic force microscope / Atomic force spectroscopy / Force curve / Force balance method / feedback control / Polymer cantilever |
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| Research Abstract |
The aim of this study was fabrication of an atomic force spectroscope with a force balancing method for surface characterizations. Some research groups had tried to measure force curves accurately by using the force balancing method, but they did not succeeded in it. In this study, we analyzed a system stability based on the feedback control theory, and it was cleared that the difficulty of measuring the force curves was caused by an insufficient frequency response of the feedback controller. When we use a AFM micro-cantilever commercially sold, the feedback controller must have frequency response of 〜100MHz. Such a frequency response is too fast to be performed by digital computer. An analog amplifier which has an enough frequency response also is of no use in the force curve measurement because of an increasing in noise level and the limit of force actuator's response.
The required bandwidth of the feedback controller can be reduced by a micro-cantilever with a high damping coefficient. Then we discussed some ways to increase the damping coefficient of the micro-cantilever by changing material and an atmosphere. Consequently a plastic micro-cantilever, especially polyimide resin, is valid to increase the coefficient. A polyimide micro-cantilever was fabricated with a micro-lithography technology and its mechanical properties were investigated experimentally. From a numerical simulation based on the mechanical properties of the polyimide resin, we found that an amplifier with 1MHz bandwidth was usable to the force-balancing system. Moreover polyimide has a good heat proof, which is suitable for measurement in a ultra-high vacuum.
We fabricated a polyimide micro-cantilever with a probe tip and a PID feedback controller with 1MHz bandwidth. However we have not measured the force curves in the term of this project.
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