掃描穿隧電子顯微鏡之即時控制軟體設計

Abstract

一個掃描穿隧式電子顯微鏡其主要架構包含：機械系統、電路系統以及電腦影像系統三部分。本研究主要是以一台自製掃描穿隧式電子顯微鏡為基礎，發展其電腦影像系統。除一般掃描圖像輸出的功能外，更針對實驗需求設計各種控制參數，以期加強實驗研究者對於操控電子顯微鏡的即時性與多樣性。 經過初步實驗後的結果，我們發現影響掃描輸出圖形品質的因素，除了探針與機械系統設計之外，軟體圖像的處理也很重要。從電路系統中所讀取到的資料必須經過適當的處理，改善對比與色調部分，才能得到與其它商業機台相同品質的影像，此外為了讓圖像品質能更提升，我們試著針對顯微鏡在室溫下工作的缺點，設計平坦化處理的演算法，藉以解決探針熱漂移等問題，使得掃瞄結果更貼近真實情況。 另外為了讓影像品質更穩定，我們考慮到掃描探針製作上可能造成的缺陷，會直接影響到取像的清析度，故本系統中設計讓探針掃描時可以有任意的行進角度，並且使用者可以選擇兩種不同的探針移動方式，以解決探針尖端不對稱所造成輸出的影像模糊。

The main structure of a scanning tunneling microscope involves three parts—namely Mechanical part, Electrics part, and Computer program. The purpose of the research is to develop a computer image system mainly based on a homemade scanning tunneling microscope. Except for the ordinary function of outputting scanned images, the design of the image system provides various parameters to satisfy the needs of the experiment, two features--real time and variety. According to the result of the experiment, the researcher found that the factors that influence the quality of outputting images are not only the design of tips and mechanical system but also the software that processes the images. In addition, the data retrieved from the circuit system have to be processed adequately. That is, by improving the contrast and the tone of colors, the same images quality retrieved from commercial system can be achieved. Besides, to improve the image quality, solve the problem of thermal drifting of tips, and make the scanning output more authentic, the researcher devised a deslope algorithm to overcome the difficulties which may occur when the scanning tunneling microscope working under the room temperature. Moreover, to make the image quality more stable, some possible defects of the making of scanning tips were taken into consideration because this may directly influence the clarity of the retrieved images. Furthermore, to solve the problem of blur images resulted from asymmetry tips, the design the system allow the scanning tips to do arbitrary angle scanning, and provides the users two different options of tips movements.