Atomic Force Microscopy And Its Image Enhancement

With the invention of Scanning tunneling microscope(STM) and Atomic force microscope(AFM), nanoscale science and technology has a rapid development in the 20 years. So, as one of the most important tools in nanoscale detection and nanoscale fabrication, AFM is receiving ever-increasing popularity in all kinds of application. Scanning Probe Microscope(SPM), which based on AFM and STM, is praised as the"eyes"and"hands"of nanoscale science and technology.At present, the lateral resolution is 0.2nm, vertical resolution is0.05nm of general commercial AFM. in recent years, with the lucubrating on biology science, scientists have begun to research the structure of small molecule. The scale of small molecule is or so 0.5nm, general commercial AFM has most difficulty to characterize these structures. So, it is the compulsory to develop high resolution AFM.The main work in this thesis is to research the design theory of AFM.IPC-208B, which combines AFM and STM and has atomic scale resolution. The basic theories which include atomic forces between probe tip and sample surface and deformation of cantilever and so on are introduced; The design theory of AFM.IPC-208B is analyzed, and its composing is given by development of AFM.IPC-208B; The keys such as workbench and data acquisition and control system are described; The method of AFM image enhancement by means of wavelet transform is researched, an improved image enhancement method based on multiscale correlation in wavelet domain is proposed, experiments show that this method can remove noise and preserve significant details. Finally, parts of testing results using AFM.IPC-208B are given., these resukts show that the instrument has good repeatability and performance, its resolution is : 0.1nm in lateral and 0.01 in vertical.The main achievements are shown as follows:1) The design theory and actualizing method of the key part in AFM system which base on STM and has atomic scale resolution are given. It use a knock-down cantilever to detect the atomic force between tip and sample, and can be used ad AFM and STM, the resolution of AFM is the same as STM. Single linear amplifier is replaced by tri- progression linear amplifier, and logarithm amplifier is used to ensure Signal-to-Noise and linearity of feedback.2) The scheme of workbench of AFM. IPC-208B that can meet quality request is...