A study on electrochemical preparation of wolfram probe used in STM

• Main Authors: Yu Huan Lin, 林鈺桓
• Other Authors: C.A.Huang
• Format: Others
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/22033554993848053782

碩士 === 長庚大學 === 機械工程研究所 === 96 === Over the past few years, the application of STM is more popular. STM relevant records are more discuss about tips manufacture methods and way to protect tips and scanning effect. Less discusses the different parameter manufacture tips difference and the mechanism of different tips. In this study, we proposed electrochemical etching method to fabricate tips in diameter about 100 nanometers. The suitable electrolyte for wolfram wire was evaluated by anodic polarization, moreover, Tip geometry was changed by varying electrochemical parameters. And use the method of partition dissociation to search the mechanism formation by the tip with the different appearance, finally use the tips with different form to carry on the scanning in STM. To test it’s scanning quality. Through the test of potentialstatic, We can know along with potential and NaOH concentration increase make the speed of dissociation go fast , When the speed of dissociation was increase that can get the probe with four different forms, There are short-thin taper tips type, two paragraph tips type, short-thin taper tips type and long taper tips type, respectively. In addition through the method of partition dissociation to discussion it four different forms mechanism, and to establishment model, explains it’s dissociation process and the mechanism. After STM scanning test, We can find short-thin taper tips has best resolution, because it’s high aspect-ratio characteristic. It is steady to enable piercing through the tunneling current, and produce better STM resolution to analyze.