The Development And Primary Application Of Multifunctional Scanning Probe Microscope

Scanning probe microscope (SPM) is a nanometer resolution imaging analysis instrument, it can obtain a resolution beyond the diffraction limit with a small probe tip scanning the sample surface. Sample information in nanometer can be studied with SPM, and it is an important tool in nano science and technology measurement. The main work of this dissertation is the development and application of multifunctional scanning probe microscope which includes AF/PSTM and AF/RSNOM.This dissertation mainly includes the following five parts:The first part is about the history, principle and application of microscope. It begins with the application of microscope, the development process of microscope from primal microscope to SPM is introduced, and the principles of scanning tunneling microscope, atomic force microscope and scanning near field microscope are presented, and appraised. The reason of developing PSTM is brought forward afar comparison with apertureless scanning probe microscope (A-SNOM) which is the only commercial SNOM, and this is the origin of this dissertation.The second part is about the near field optics theories. In the macroscopical near field optics theory, four main theories are introduced: Maxwell equations and boundary conditions method, approximate perturbation method used in sample with small fluctuation and periodic structures, expansion in multipoles method suited to sample with localized geometries, and finite-difference time domain method used in sample with several wavelengths size. In the macroscopic and microcosmic near field optics theory, the Propagator or Green dyadic method and polarization method based on the scattering theory are introduced. Although these methods avoidcomplicated boundary conditions problem, but the analysis solutions of Green dyadic is difficult to obtain in complex sample, so it can only be used in simple sample. These methods are the basis of near field optics.The-third part is the development of AF/PSTM and its experiment results. Because there are artifacts in origin PSTM optical image, the development of AF/PSTM starts with the theory of optical artifacts elimination. The system designing is according to the requirement of AF/PSTM. The designing of the mainframe, the circuits, the software and the main elements of AF/PSTM such as the bent optical fiber probe, the scanner piezoelectricity tube are introduced. The p polarization symmetry beams illumination method and the image explanation are also presented. In order to realize the noninterference p polarization symmetry illumination, a total inner reflection sample stage is designed to improve the p polarization, and the two incident light beams are emitted from different laser diodes in horizontal direction and total reflected from the sample surface. The horizontal direction incidence makes the adjusting of the incident light easier, and the illumination light beams from different laser diodes are noninterference, which avoid the interference problem in the optical images. The function of AF/PSTM is examined and experiment results are offered. This AF/PSTM technique is used in nanometer oil additive and the results is consistent with the railway measurement, which shows that AF/PSTM can be used as a measurement method in nanometer oil additive to save costly measurement expenses. AF/PSTM technique is also used in immunoreaction compound and gets expected results.The fourth part is the development and experiment of AF/RSNQM, AF/RSNOM is exploited on the basis of AF/PSTM. This tapping mode AF/RSNOM is brought forward after analysis of former RSNOM in theory and experiment. The principle, the image obtaining and the results with its explanation are provided.The end part is the conclusions and expectation of this dissertation, where the problems and future of multifunctional scanning probe microscope are put forward.The results show:? The aim of AF/PSTM is obtained: the resolution is beyond the diffraction limit, the samples' AFM images and PSTM images can be get simultaneously, eliminating the artifacts in optical image for asymmetry illumination, can be used in many fields. AF/PSTM is signality in biomedicine and nano science and technology development.? The tapping mode AF/RSNOM uses a fiber probe tip as both illumination element and collection element in near field of sample surface, which not only bring an even illumination, but also bring simple manipulation. The optical image signal to noise ration of tapping mode AF/RSNOM is higher than that of other RSNOM without tapping mode.