The Development of Scanning Probe Microscope
| Autor: | Shiu, Wen-Tze, 許文澤 |
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| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 97 Based on the framework of our home-made scanning tunneling microscope (STM) system, this study is focused on the improvement of stability. There are two major parts, mechanical design and electronics, in this improvement. Regarding to the mechanical design, springs with more suitable stiffness and rubber feet were used to damp environmental vibration efficiently. The wiring connecting the STM stage and the electronic control-box was rearranged to decrease the number of joints, from which the external vibration is introduced into the STM stage. The bias for tunneling was modified to apply on the tip, which is on the opposite side to the scanner, to avoid the problem of leakage current and improve the resolution in the Z-direction. Instead of naked eye, we used a CCD camera to observe the distance between the tip and the sample for convenience and preventing the tip crashing in approaching process. As to the electronics, the parallel port was replaced by USB for communication interface. The IC with higher processing speed was used in preamplifier. This improvement on the electronics avoids the noise and artifacts resulted from the circuits. After improving the STM system, we added an atomic force microscope (AFM) mode by using a tuning fork as the feedback sensor. We used the AC signal, which was acquired as the tuning fork was driven to oscillate at the resonant frequency, for feedback with amplitude-modulation mode. Combining the tuning fork sensor with the scanner and electronics circuit of our improved STM system, we have obtained AFM images roughly. We have constructed a simple scanning probe microscope (SPM) system with the STM mode and the AFM mode. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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