本篇論文中，我們主要以光激螢光光譜(photoluminescence, PL)、表面光電壓光譜(surface photovoltage spectroscopy, SPV)、無接點電電場調製反射光譜(contantless electroerflectance, CER)、壓電調制反射光譜(peizoreflectance, PzR)暨光子調制反射光譜(photoreflectance, PR)量測技術探討壓縮應力銻砷化鎵/砷化鎵量子井(GaAs1-xSbx/GaAs QW)及應力補償型銻砷化鎵/磷砷化鎵量子井(GaAs1-xSbx/GaAs1-xPx QW)之光學特性。所量測的量子井樣品係利用有機金屬化學氣相沉積法(metal organic vapor phase epitaxy, MOVPE)成長於砷化鎵基板之上。從光激發螢光光譜實驗結果中，可以觀察到各個樣品基態1e-1hh的訊號，亦可發現加入磷砷化鎵位障層之樣品會有較強的發光強度。從低溫下之激發源功率相依之光激發螢光光譜實驗中，也可佐證在較高銻含量的GaAsSb/GaAs量子井峰值會隨著激發功率的增加，會有明顯的藍移，使吾人可以判定此樣品為第二型量子井能帶結構，而在GaAsSb/GaAsP的樣品則有較小的藍移，為第一型量子井能帶結構，發光特性較佳。另外藉由調製反射光譜與表面光電壓光譜觀測到量子井中可能的光學躍遷訊號之外，同時可量測到從位能障受應力分裂輕電洞(LH)與重電洞(HH)的訊號，得以直接利用於理論計算。從比對實驗結果與量子井理論計算，我們可以確認出所有激子躍遷信號的能量位置，並得到各個樣品量子井中應力的相關信息以及能隙補償差(conduction band offset, Qc)的大小，並從結果可以觀察到，加入磷砷化鎵位障層的樣品會有較大的應力釋放以及較高的導電帶高度。

A detailed optical characterization of compressive-strained GaAs1-xSbx/GaAs and strain-compensated GaAs1-xSbx/GaAs1-yPy triple quantum well (TQW) structures grown by metal organic vapor phase epitaxy (MOVPE) has been carried out by using photoluminescence (PL), surface photovoltage spectroscopy (SPS), and modulation spectroscopy. For GaAs1-xSbx/GaAs TQW with Sb content x=0.36, only a very weak photoreflectance (PR) feature is observed in the vicinity of fundamental transition and large blue shifts of the PL peak position with increasing of excitation power density, which has been attributed to a weakly type-II heterojunction formed between GaAsSb and GaAs. The PR and SPS spectra of GaAsSb/GaAsP TQW display a series of features originated from interband transitions which is a typical characteristic of type-I QW structure. Utilizing the experimentally deduced GaAsP conduction to heavy- and light-hole band gap energies, we can make an unambiguous determination in the barrier heights for the heavy hole and light hole wells. In order to identify the observed intersubband excitonic transitions, a strain compensation factor r and conduction band offset Qc are used as the parameters for theoretical calculations. The obtained value of r and Qc are found to be Sb content dependent. The results indicate that the energy band of strain-compensated QW structures is significantly influenced by replacing GaAs with GaAsP barriers, which improve the electron confinement and reduce the compressive strain of the well. The strain-compensated GaAsSb/GaAsP TQWs have a larger overlap integral and hence a higher transition probability, providing a possibility for fabricating high efficiency near infrared laser diodes.

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