Apply XAFS In The Research Of Semiconducior Materials And Research Method Innoatio

This article is making use of the principle of synchrotron radiation,emphatically introduces the branch in synchrotron radiation absorption fine structure of the synchrotron radiation technology characterization(X-ray absorption fine structure,XAFS),and giving a comprehensive introduction to the principle and application of this technology.The author gradually deepening the practical methods of characterization by using the X-ray absorption spectroscopy detection principle of microstructure of semiconductor material,experiment the equipment and technology of XAFS,and analysis the advantages and disadvantages of the XAFS spectral analysis of traditional analysis methods,even a new method of innovation.This paper focuses on the analysis of advantages and disadvantages of traditional XAFS spectrum analysis methods.At the beginning of 1971,the XAFS analysis means gradually was demonstrated and the use of science.Although the XAFS has experienced more than 40 years,but it is still a relatively young structure analysis technology,therefore,the traditional method is still widely studied and used in the field.The author also put the traditional analysis method used in semiconductor materials(6H-SiC041,050,054,177;AlGaN401,402,403),analyzed the structure characteristics of the two sets of samples.Due to the traditional method requires Fourier transform to filtering and back-and-forth fitting,therefore,it needs a lot of time to test to get a good result.The most important is,when the sample structure is complex,or experimental data cannot be used well discrete Fourier transform,cannot use the existing model to fit the structure.To solve this problem,the author propose a new method that makes up for the shortcomings of traditional methods.The new method take attention onto the zeros of the ?(k)which is the key to the solution.When we consider a zero-point of the ?(k m),where km(m=1,2,3..)are the roots of ?(k),It is obvious that,the multiples to the right side of x(k)become unimportant,as a zero times anything is still zero.The tedious multiple parameter fitting is now reduced to a set of algebraic equations.By logical deduction and analysis,obtained in experiment specrum of shock wave vector space has zero center atom and atom scattering,the use of Matlab for the minimum algorithm,we can easily find the parameter we need,such as the first shell of the central atom,the second shell bond length,coordination number and other parameters.In this way,we no longer need to back-and-forth fitting and complex Fourier transform to filtering,but very easy to get the important structural parameters we need.Theory of the new method is completed,first using the data of FeO published in 2004 by Matthew Newville,the results are very credible.Then extend the method to the existing experimental data on(6H-SiC 041,050,054,177,AlGaN 401,402,403),the test results is very similar with the results obtained by the repeated fitting.Although the author proposed new method and provided a rigorous logical derivation and established the operation process,but there are still many problems need to be solved,such as for the refinement of the internal parameters of the structure,expand to third layers,fourth layers or more layers,these problems need to solve in future.