具銻砷化銦鎵披覆層之砷化銦量子點特性研究; Improving Long Wavelength InAs Quantum Dots by an InGaAsSb Overgrown Layer

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Title:	具銻砷化銦鎵披覆層之砷化銦量子點特性研究;Improving Long Wavelength InAs Quantum Dots by an InGaAsSb Overgrown Layer
Authors:	蕭孟杰;Meng-Jie Shiau
Contributors:	電機工程研究所
Keywords:	銻砷化銦鎵;銻;InGaAsSb;antimony
Date:	2007-07-04
Issue Date:	2009-09-22 12:06:49 (UTC+8)
Publisher:	國立中央大學圖書館
Abstract:	本論文探討以銻砷化銦鎵做為量子點披覆層，對砷化銦量子點產生的的影響。藉由室溫光激發光譜我們觀察到披覆銻砷化銦鎵的量子點發光波長會產生紅位移的現象，波長可以延伸到1.4 μm以上，並且維持相當好的發光強度。經由掃描式穿透式電子顯微鏡，我們發現紅位移的原因主要來自於量子點大小的變化，銻在此效應所扮演的角色亦一併提出討論。除此之外，經過快速熱退火(rapidly thermal annealing)實驗發現，披覆銻砷化銦鎵的量子點有較好的耐熱性，即使在經過20秒750 oC的熱處理之後，仍然可以維持原來的發光特性，遠佳於披覆砷化銦鎵的量子點。因此，我們認為可能是銻化合物抑制了銦原子和鎵原子的互混，但是此假設仍需進一步的研究以釐清。由以上結果可以得知，砷化銦量子點覆蓋銻砷化銦鎵是一個良好的磊晶結構，對長波長量子點光電元件極有助益。 In this work, the material aspect of InAs quantum dot heterostructures grown on GaAs by molecular beam epitaxy is investigated. With the addition of Sb to an InGaAs overgrown layer, the ground state emission of InAs quantum dots is red-shifted from 1346 nm to 1390 nm at room temperature while maintaining high luminescence intensity. Cross-sectional scanning transmission electron microscopy (STEM) studies indicate that the redshift of emission wavelength could be attributed to the increase of dot size. The average height of the InAs quantum dot with an InGaAsSb overgrown layer is 9.3 nm compared to 8.5 nm for the dots with an InGaAs overgrown layer. The role of Sb in the increase of dot size is proposed. The robustness at high temperature for the InAs QDs with an InGaAsSb overgrown layer is also enhanced as evidenced by the rapid thermal annealing experiments in an N2 ambient. The sample with an InGaAsSb overgrown layer survives thermal treatment up to 750 oC for 20 seconds. The mechanism of the suppression of In-Ga intermixing by this Sb-based material is not clear and requires further investigation. In spite of this, the results of this study indicate that InGaAsSb overgrown layer is indeed beneficial for long wavelength InAs quantum dot photonic devices.
Appears in Collections:	[Graduate Institute of Electrical Engineering] Electronic Thesis & Dissertation

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