本篇論文以變功率的光激發螢光實驗在研究以不同溫度成長之InGaAs量子點(Quantum Dot , QD)與量子井(Quantum Well , QW)結構，並觀察量子點與量子井GaAs的螢光能量位置及強度隨激發光強度變化。我們發現在低激發功率下，光激發螢光光譜上波峰位置並不會隨激發功率的變化而改變；但在高激發功率下，光激發螢光光譜上波峰位置會隨機發功率的增加而增加。將激發功率取對數值對光激發螢光光譜上波峰位置作圖後發現在QW的部分會達飽和(saturate)，而在QD的部份則無此飽和的現象，這是由於QD之能態態密度(density of state)為δ函數之緣故。QD能量位移常數 之值大於QW之 值。此外，改變激發光的強度，來探討不同量子結構的發光效率，實驗結果顯示QD之發光效率較QW好。最後藉由因變化激發功率所造成熱電子的效應並找出GaAs(111)的LO聲子能量，其能量約為36meV。

The power-dependent photoluminescence (PL) measurement were taken on InGaAs quantum dots (QDs) and quantum wells (QWs) grown at different temperatures. The PL peak position is independent on pumping power for QDs and QWs under lower power excitation while it increases as the pumping intensity increases under high power excitation. The increasing peak position approaches to a constant value for QWs and this behavior is not observed for QDs dues to the delta-functional density of states. The energy shift constant,β,evaluated from the relation between peak position and the pumping power, and the radiative efficiency of QD are larger than that of QW. Finaiiy, the GaAs(111) LO-phonon energy can be estimated as about 36meV from the higher energy side of the GaAs PL specturm.

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