本論文為利用光反射調制光譜(PR)、非接觸電場調制反射光譜(CER)、 壓電調制反射光譜(PzR)、表面光電壓(SPV)、與光激發螢光光譜(PL)等光學技術，研究銻砷化鎵/砷化鎵量子井(GaAsSb/GaAs)與具應力補償之銻砷化鎵/磷砷化鎵量子井(GaAsSb/GaAsP)及銻砷化鎵/砷化鎵/磷砷化鎵(GaAsSb/GaAs/GaAsP)量子井材料之光學特性。量測之樣品是以水平有機金屬化學氣相沉積系統(AIXTRON-200)於n型摻雜之砷化鎵基板上，成長壓力與溫度分為50 mbar及525℃，TEGa、TMSb、AsH3及PH3分別作為鎵、銻、砷、磷的前驅物(Precursor)
在銻砷化鎵/砷化鎵量子井部分，GaAs0.64Sb0.36/GaAs樣品之PR譜線，在其基態躍遷區域僅有非常微弱躍遷訊號，在低溫下之激發源功率相依之PL實驗中，其譜線則有明顯的藍移現象，此乃因此樣品之GaAs0.64Sb0.36與GaAs之介面為近第二型量子井結構所致。
在銻砷化鎵/磷砷化鎵與銻砷化鎵/砷化鎵/磷砷化鎵兩種樣品之PR, CER, PzR及SPV譜線中，顯示第一型量子井結構所具有一系列躍遷訊號，因其結構具有應力補償之效果，因此由其PR譜線有激子躍遷之訊號。另外其磷砷化鎵位障層(barrier)可發現因伸張應力而分裂之輕電洞(LH)與重電洞(HH)的訊號，且輕電洞應較重電洞有較高能量，並可與理論計算吻合。在其量子井之激子躍遷由實驗結果與量子井理論計算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導電帶偏移(Conduction Band Offset, Qc)的大小。
銻砷化鎵/砷化鎵/磷砷化鎵部分，因其結構具應力補償，因此其PR譜線與DSPV譜線均有激子躍遷訊號，並比銻砷化鎵/磷砷化鎵之訊號更為豐富。由PL與PR譜線，我們得知此結構之量子井材料，且其主要躍遷E0 能量已對應於1.3μm，可達到於光通訊應用之期待。

Abstract
Optical characterization of strained GaAsSb/GaAs quantum well (QW) as well as strain-compensated GaAsSb/GaAsP and GaAsSb/GaAs/GaAsP QW structures has been carried out by using photoreflectance (PR), contactless electroreflectance (CER), piezoreflectance (PzR), surface photovoltage (SPV) spectroscopy and photoluminescence (PL) techniques. The samples employed in this study were grown on n+ GaAs (100) substrates by using a horizontal metal organic vapor phase epitaxy system (AIXTRON-200) equipped with an IR-lamp heater. The total pressure and growth temperature of reactor were 50 mbar and 525 ºC, respectively. TEGa, TMSb, AsH3 and PH3 were used as the precursors for Ga, Sb, As and P sources.
For GaAs0.64Sb0.36/GaAs QW structures, only a very weak PR feature observed in the vicinity of fundamental transition and a large blueshift of the peak position of PL feature with increasing of excitation power density has been attributed to a weakly type-II heterojunction formed between GaAs0.64Sb0.36 and GaAs.
The PR, CER, PzR and SPV spectra of GaAsSb/GaAsP and GaAsSb/GaAs/GaAsP QWs 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 light-hole and heavy-hole band gap energies, we can make an unambiguous determination in the barrier heights for the light-hole and heavy-hole wells. In order to identify the interband transitions, a calculation was performed based on the envelope function approximation using the conduction band band-offset Qc and strain compensation factor γ as adjustable parameters. The obtained values of Qc and γ are found to be Sb content dependent. The results indicate that the energy band of strain-compensated QW structure is significantly influenced by replacing GaAs barrier by GaAs0.79P0.21 layers, which changes the weakly type-II to a type-I structure. In addition, the effects of insert a GaAs layer between GaAsSb and GaAsP are discussed. The strain-compensated GaAsSb/GaAsP and GaAsSb/GaAs/GaAsP QWs have larger overlap integrals and hence higher transition probabilities, providing a possibility for fabricating high efficiency near infrared laser diodes.

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