銻磷化銦結構特性與拉曼光譜之研究

本論文旨在分析銻磷化銦(InPSb)三元合金系統的結構特性，研究其拉曼光譜，並分析其嚴重的鍵結畸變(bond distortion)所帶來的影響。我們利用氣態源分子束磊晶在砷化銦(InAs)基板上成長了一系列的銻磷化銦，從高解析X光散射(XRD)發現銻含量0.36的樣品具有單晶的特徵，而其他樣品譜線半寬則發生了異常，產生了相分離的現象，代表其濃度波動甚大，從倒置晶格空間圖譜(RSM)中可以發現，單晶的樣品仍受應力影響，存在良好的長距結構有序(Long-range order)，但相分離的樣品則產生失序的現象。研究短距結構(Short-range order)的過程中，我們利用同步輻射光源來取得材料的X光吸收精細結構(Extended X-ray Absorption Fine Structure)，再由ARTEMIS與ATHENA軟體分析來取得合金中磷化銦的鍵長，及相關的Debye-Waller因子，結果顯示樣品鍵長皆趨近於二元合金，且與利用價力場模型(Valence Force Field)計算的結果相近，顯示了架構上仍存在著閃鋅結構(Zincblend)，接著我們討論了Debye-Waller因子在X光散射理論中，與同步輻射理論中之不同，並探討實驗結果其背後的原因，而由於樣品具有長距有序，且符合價力場模型的計算，因此儘管鍵結存在著嚴重畸變，卻仍能在X光散射中有良好的譜線半寬；然而銻含量0.17相分離樣品之鍵長存在異常，且無法與價力場模型一致，顯示其長距結構存在失序，我們認為此樣品之鍵結畸變能已透過產生缺陷的方式來消除。另一方面，我們進行的拉曼量測裡，解析了銻化銦相關模態、磷化銦相關模態，以及由於失序而啟動的聲學聲子(DALA)。在選擇規則的測試中，我們認為磷化銦具有一鍵雙模(1-bond 2-mode)的特性，而非以往文獻上記載之一鍵一模(1-bond 1-mode)，從極化圖(polar plot)的實驗發現，銻含量0.36單晶樣品的三種模態性質都不同，由價力場模型分析，取得不同次鄰接原子結構的伸張畸變能(stretching distortion energy)與彎曲畸變能(bending distortion energy)，認為當某一銦原子周圍是2磷2銻(2P2Sb)時，會產生較高頻率之磷化銦模態，因為其具有最低的伸張畸變能，但擁有較高的彎曲畸變能將阻礙這種模態遵循一般之振動方式；而所有在銻含量0.17相分離樣品中的模態，皆顯現出不對稱的震動方式，脫離拉曼量測對稱群的振動方式，表示著它們都被樣品中缺陷震動所影響。

關鍵字

銻磷化銦；鍵結畸變；長距結構有序；相分離； X光吸收精細結構；拉曼散射；失序啟動聲學聲子；一鍵雙模；價力場模型；滲透模型；拉曼選擇規則；缺陷

並列摘要

We grew a series of InP1-xSbx on (0 0 1) InAs substrate by gas-source molecular beam epitaxy, and reported on the structural properties of ternaries with two Sb composition, x = 0.17 and x = 0.36. Results from high resolution x-ray diffraction (XRD) and reciprocal space mapping (RSM) show that the sample with x = 0.17 suffers from phase separation while the sample with x = 0.36 is of good crystallinity and coherently strained to the substrate. For the latter sample, the InP bond length obtained from extended X-ray absorption fine structure (EXAFS) coincides with the value from valence force field (VFF) calculation, and the mean atomic deviation from the zincblende lattice is zero. We have shown that because of the zero mean, the XRD and RSM are not affected by the internal distortion. For the sample with x =0.17, the InP bond length obtained from EXAFS is much shorter than the value calculated by VFF model, suggesting the loss of long range order, i. e., the mean of atomic deviation is not zero, in other words, the zincblende lattice from which the atoms deviate no longer exists and the long range order is lost. We believe that the bond distortion in this sample has been partially released through defect generation. Raman scattering also supports these findings. The sample with x = 0.17 shows distinct InP-like and InSb-like modes. While the InP-like modes of the sample with x = 0.36 merge to a wide band, which is attributed to a one-bond-multi-mode behavior induced by the internal distortion. Polar plot with the analyzer aligned to [1 0 0] was used to quantify the effect of distortion on the modes. The three modes for the sample with x = 0.36 show different behaviors. The influence of internal distortion decreasing with the decreasing bending distortion. The strong bending distortion hinders the bond to obey the normal vibration. In the sample with x = 0.17, the three modes are all dominated by asymmetry vibration, suggesting that they are activated by defect vibration. Due to the complexity of these modes, we label the high frequency peak as InP-like I while InP-like II accounts for the low frequency end in the final.

並列關鍵字

InPSb ； bond distortion ； long range order ； phase separation ； EXAFS ； Raman scattering ； 1-bond 2-mode ； DALA ； Percolation model ； Valence Force Field ； Raman selection rule ； defect

參考文獻

[1] A. Krier, “Room‐temperature InAsxSbyP1−x−y light‐emitting diodes for CO2 detection at 4.2 μm,” Appl. Phys. Lett. 56, 2428–2429 (1990).

[2] M. K. Parry and A. Krier, “Room-temperature Cd-diffused InAsSbP diodes for methane gas detection,” Semicond. Sd. Technol. 8, 1764-1769 (1993).

[5] N. Koca, N.A. Kocaoglu-Vurma, W.J. Harper and L.E. Rodriguez-Saona, “Application of temperature-controlled attenuated total reflectance-mid-infrared (ATR-MIR) spectroscopy for rapid estimation of butter adulteration,” Food Chemistry. 121, Issue 3, 778–782 (2010)

[6] J. Wagner, C. H. Mann, M. Rattunde and G. Weimann, “Infrared semiconductor lasers for sensing and diagnostics,” Appl. Phys. A, 78, 505–512 (2004).

[7] C. J. Wu, Z. C. Feng, W. M. Chang, C. C. Yang, and H. H. Lin, “Bond lengths and lattice structure of InP0.52Sb0.48 grown on GaAs,” Appl. Phys. Lett. 101, 091902 (2012).

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銻磷化銦結構特性與拉曼光譜之研究

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