本文選題：X射線精細(xì)結(jié)構(gòu)譜學(xué) + (XAFS)　； 參考：《廣西大學(xué)》2017年碩士論文

【摘要】：本文著重介紹同步輻射這項(xiàng)表征手段的分支技術(shù)——X射線精細(xì)結(jié)構(gòu)譜學(xué)(X-ray absorption fine structure,XAFS),較為全面的介紹了這項(xiàng)技術(shù)的原理和應(yīng)用。全文從XAFS探測(cè)半導(dǎo)體材料微觀結(jié)構(gòu)的原理、XAFS的實(shí)驗(yàn)設(shè)備及技術(shù)、X射線精細(xì)結(jié)構(gòu)譜傳統(tǒng)分析手段的介紹與優(yōu)劣勢(shì)分析、新方法的創(chuàng)新逐步深入分析這項(xiàng)實(shí)用的表征手段。本文的重點(diǎn)在于X射線精細(xì)結(jié)構(gòu)譜傳統(tǒng)分析手段的介紹與優(yōu)劣勢(shì)分析。從1971年開(kāi)始,XAFS理論分析與數(shù)據(jù)處理才逐漸被科學(xué)的論證和使用。目前,XAFS經(jīng)歷了 40多年的發(fā)展并日漸成熟,在該領(lǐng)域傳統(tǒng)方法被廣泛學(xué)習(xí)和使用。同時(shí)也不乏該領(lǐng)域的研究人員在進(jìn)行理論研究和數(shù)據(jù)處理方法創(chuàng)新。作者將傳統(tǒng)分析手段應(yīng)用于半導(dǎo)體材料(6H-SiC 041,050,054,177;AlGaN 401,402,403)中,分析了這兩個(gè)系列樣品的結(jié)構(gòu)特性。由于傳統(tǒng)方法需要進(jìn)行反復(fù)的傅里葉變換和擬合,以至于需要花費(fèi)大量時(shí)間調(diào)試才能得到一個(gè)好的結(jié)果。最為重要的是,當(dāng)樣品的結(jié)構(gòu)復(fù)雜或者實(shí)驗(yàn)數(shù)據(jù)使用傅里葉變換無(wú)法很好的分立殼層時(shí),這些情況下無(wú)法用已有的結(jié)構(gòu)模型去擬合。因此,為了解決這個(gè)問(wèn)題,課題組合作導(dǎo)師許谷院士(加拿大麥克馬斯特大學(xué)教授,加拿大工程院院士)提出了一個(gè)新方法[1],用于彌補(bǔ)傳統(tǒng)方法的缺陷和短板。新方法從X射線精細(xì)結(jié)構(gòu)譜震蕩基本原理公式出發(fā),抓住震蕩譜形在取某些km值時(shí),使得等式右邊為零的特點(diǎn)[1],將擬合整條曲線進(jìn)而得到未知參數(shù)的問(wèn)題,轉(zhuǎn)變?yōu)榻釴個(gè)方程組的問(wèn)題。通過(guò)邏輯推導(dǎo)和分析論證,在求得實(shí)驗(yàn)譜波矢空間的震蕩零點(diǎn)以及中心原子和散射原子的相位后,利用Matlab求最小值的算法,可以非常容易的找到使用者需要的參數(shù)。如中心原子的第一殼層、第二殼層的鍵長(zhǎng),配位數(shù)等。這樣,使用者可以非常簡(jiǎn)便的得到需要的重要結(jié)構(gòu)參數(shù),而不再需要反復(fù)的傅里葉變換和擬合。新方法的理論推導(dǎo)完成后,首先運(yùn)用在Matthew Newville于2004發(fā)表的FeO材料上使用[2],發(fā)現(xiàn)結(jié)果非�？尚�。進(jìn)而推廣到已有的實(shí)驗(yàn)數(shù)據(jù)上(6H-SiC 041,050,054,177,AlGaN 401,402,403),分析結(jié)果與反復(fù)擬合得到的結(jié)果非常相近。雖然本文對(duì)于介紹的新方法提供了較為嚴(yán)密的邏輯推導(dǎo)并初步確定了操作流程,但是仍然還有很多問(wèn)題需要繼續(xù)研究和解決,如求rm內(nèi)部參數(shù)的細(xì)化,結(jié)構(gòu)擴(kuò)張到第三層、第四層甚至更外層等問(wèn)題。在逐步完善這些理論和方法后,本文介紹的方法將可以適用于更廣泛的材料領(lǐng)域。
[Abstract]:In this paper, the branch technique of synchrotron radiation (synchrotron radiation), X-ray absorption fine structure, X-ray fine structure spectroscopy, and its principle and application are introduced in detail. Based on the principle of detecting the microstructure of semiconductor materials by XAFS, this paper introduces the experimental equipment and technology of XAFS and analyzes the advantages and disadvantages of the traditional analysis methods of X-ray fine structure spectrum. The innovation of the new method is used to analyze this practical characterization method step by step. The emphasis of this paper is on the introduction and advantage and disadvantage analysis of X-ray fine structure spectrum. Since 1971, XAFS theory analysis and data processing have been scientifically demonstrated and used. XAFS has been developed for more than 40 years, and has been widely studied and used in this field. At the same time, there are many researchers in the field of theoretical research and data processing methods innovation. The author applied the traditional analytical method to the semiconductor material 6H-SiC 041050054177AlGaN 401402403) and analyzed the structural properties of the two series samples. Because the traditional method needs repeated Fourier transform and fitting, it takes a lot of time to debug to get a good result. The most important thing is that when the structure of the sample is complex or the experimental data can not be well separated by Fourier transform, the existing structural model can not be used to fit these cases. Therefore, in order to solve this problem, a new method [1] was proposed by our co-mentor, Academician Xu Gu (Professor McMaster University, Canadian Academy of Engineering), to make up for the defects and shortcomings of traditional methods. Based on the basic principle formula of X-ray fine structure spectral oscillation, the new method holds the characteristic that the oscillatory spectral form is zero to the right of the equation when some km values are taken, and the unknown parameters can be obtained by fitting the whole curve. The problem of solving N equations. Through logical derivation and analysis, after finding the oscillatory zero point in the spectrum vector space and the phase of the center atom and the scattering atom, the parameters needed by the user can be easily found by using the algorithm of Matlab to calculate the minimum value. For example, the first shell of the central atom, the bond length of the second shell, the coordination number, etc. In this way, the user can easily get the important structural parameters without the need of repeated Fourier transform and fitting. After the theoretical derivation of the new method is completed, the method is first applied to the FeO material published by Matthew Newville in 2004, and the results are very reliable. It is further extended to the experimental data of 6H-SiC 041050054177AlGaN 4014024030.The analytical results are very close to those obtained by repeated fitting. Although the new method presented in this paper provides a more rigorous logical derivation and a preliminary determination of the operation flow, there are still many problems to be continued to be studied and solved, such as the refinement of the internal parameters of RM, the expansion of the structure to the third layer. The fourth layer or even the outer layer, etc. After perfecting these theories and methods, the method presented in this paper can be applied to a wide range of material fields.
【學(xué)位授予單位】：廣西大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：O434.1;TN304

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本文編號(hào)：1930484