鍺/矽/鍺多層量子點結構之光學特性研究

Optical properties of Ge/Si/Ge quantum dot in multilayer structure

陳弘斌(Hung-Bin Chen)

指導教授 ： 徐子民

國立中央大學/理學院/物理學系/碩士(2011年)

摘要

本論文利用光致螢光光譜來分析鍺/矽/鍺量子點結構的光學特性，並對試片做快速熱退火處理來嘗試改善發光效益，同時與鍺/矽量子點結構的量測結果做比較，研究結構上的差異對光譜能量和強度上的影響。由不同熱退火溫度試片的螢光能量與激發功率的分析中，我們得知鍺/矽/鍺量子點結構的原子擴散程度較高，有著較高的螢光能量和較淺的載子侷限位能。由不同量測溫度下螢光強度與激發功率的分析中，我們得知被侷限在缺陷中的電子在低溫下會吸收螢光，降低發光的效益。最後我們從螢光強度與量測溫度的分析中，得知鍺/矽/鍺量子點有著較高的活化能，推測電洞可藉由穿隧效應存在長晶方向上鄰近的量子點內。

關鍵字

鍺量子點 ； 光學

並列摘要

In this paper, we have studied the optical properties of Ge/Si/Ge quantum dots (QDs) structure by using Photoluminescence (PL) spectroscopy.And we use rapid thermal annealing process to improve its light efficiency.Comparing the PL measurements of Ge/Si/Ge QDs structure with Ge/Si QDs structure, the structural difference effect on optical properties is studied.
According to the emission energy of annealed samples in excitation-powerdependent PL measurements, we found that Ge/Si/Ge QDs structure has higher emission energy and lower carriers confinement depth due to atomic intermixing
effect. According to the PL intensity with power sublinear relation at different temperature measurements, we suggest that the defect has negative effect on light efficiency because emitting light will be absorbed by the electrons confined in the defect. Finally, we found that the Ge/Si/Ge QDs structure has higher activation energy from Temperature-dependent PL measurements. Therefore, we
point out that the holes in Ge/Si/Ge QDs structure probably can exist on nearby QDs by tunneling effect.

並列關鍵字

Ge quantum dots ； optical properties

參考文獻

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