應用X光繞射,延伸X光吸收細微結構及光致發光量測與分析纖鋅礦結構的氮化銦材料之晶格與電子特性

Measurement and Analysis of Structural, Electronics Properties of Wurtzite Indium Nitride using X-ray Diffraction, Extended X-ray Absorption Fine Structure and Photoluminescence

黃于桓(Ferry Wiryo Pranoto)

指導教授 ： 林浩雄

國立臺灣大學/電機資訊學院/光電工程學研究所/碩士(2015年)

https://doi.org/10.6342/NTU.2015.01178

摘要

本論文的研究主題是量測與分析氮化銦(InN)纖鋅礦晶格結構的晶格常數a，c，鍵結常數 (bond length) ，c/a，以及internal parameter u (b/c)。我們先應用X光繞射求出晶格常數a，c。之後我們再用X光吸收譜來求出纖鋅礦晶格的原子距離(bond length)。我們選擇In K-edge量測分析EXAFS(extended X-ray absorption fine structure)，我們利用X光繞射求出來的晶格常數a，c當作EXAFS擬合的基本參數。
總合HR-XRD,EXAFS的結果,我們成功求出InN半導體的晶格參數a，c，銦-氮的建長，c/a，以及u。我們算出來的u擁有誤差小於10-3Å。
我們再利用photoluminescence量測氮化銦的發光波段.我們發現氮化銦的發光波段在於遠紅外(~ 0.7 eV).造成發光的機制是由導帶的電子躍遷到價帶上面的acceptor state。

關鍵字

氮化銦 ； X光繞射 ； EXAFS ； 晶格常數a,c ； 銦-氮建長 ； b/c

並列摘要

This master thesis is about studying crystal structure properties of wurtzite structure Indium Nitride using high resolution X-ray diffraction spectroscopy (HR-XRD), and In k-edge Extended X-ray Absorption Fine Structure (EXAFS). The result of HR-XRD does not suffice in resolution since lattice constant results from two different planes differ around 0.13%. We then apply mathematical model to correct the value of the measured lattice constant. The mathematical corrected result of our lattice constant a is ~ 3.53154 to 3.53204 Å, lattice constant c is ~ 5.70437 to 5.70565 Å. Our corrected HR-XRD measurement result has error bar under 10-8 Å. Lattice constant a and c of our samples show significant trend in which whenever the crystal is expanded in basal plane (elongate lattice constant a), the crystal structure will contract in its height (shown in shortened of lattice constant c) and vice versa.
We then establish crystal model of wurtzite InN to fit the In k-edge of EXAFS data using the corrected HR-XRD lattice constants. Using combination data from both HR-XRD and EXAFS we could complete the structural measurement of wurtzite InN. We succeed in measuring 1st nearest neighbor (bonds length between In and N), 2nd nearest neighbor (In – In), with these parameters we could then derive wurtzite crystal structure c/a is 1.6152, and internal parameter u (b/c) is 0.3765. We successfully demonstrate the capability of EXAFS and HR-XRD to measure the internal parameter u with error around 10-3A. We notice that despite the lattice different around sample to sample, internal parameter u result shows stability indicating there exists a bonding force to keep the unit tetragonal cell intact by altering their bonding angle.
Our study is continued with photoluminescence measurement of InN, with most sample has single peak at 0.68-0.7 eV that correspond to conduction band to acceptor transition.

並列關鍵字

HR-XRD ； EXAFS ； wurtzite lattice constant a,c ； bond length ； internal parameter u

參考文獻

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