砷化氮鎵/砷化鎵 三井量子結構的光譜研究

Abstract
我們利用光調制反射光譜(PR)及螢光光譜(PL)來研究由MOCVD長成的GaAs/GaNxAs1-x 三量子井結構樣品。藉由光調制反射光譜的溫度變化,實驗結果發現砷化鎵能隙與量子井能階躍遷訊號都是隨著溫度的升高,單純地往低能量偏移的現象。 由螢光光譜的實驗結果,我們觀察到砷化鎵能隙與量子井的相關訊號。藉由螢光光譜的溫度變化,發現砷化氮鎵量子井相關訊號存在著一個不尋常的發光現象,隨著溫度的升高,其峰值能量的改變呈現先藍移再紅移的能量變化。 在GaNxAs1-x/GaAs三量子井結構的PR實驗結果中,藉由量子井躍遷的訊號,我們以type Ⅰ的能帶結構來計算GaNxAs1-x電子的有效質量,得到GaNxAs1-x電子的有效質量分別為0.19m0 及0.10m0。本論文並探討經過快速熱退火處理(RTA)的樣品,其量子井躍遷訊號能量及強度有何變化。
We have investigated the interband transitions in GaNAs/GaAs triple quantum wells by photoluminescence and photoreflectance. The samples used in our experiments were grown by Metal-Organic Chemical Vapor Deposition. The photoreflectance spectral peaks of the quantum well transitions were blue shifted as the temperature decreased. In the photoluminescence, the spectral peaks were red shifted as the temperature decreased below 50 K. The anomalous red shift may be due to the carrier localization at potential fluctuations. The interband transition energies for GaNAs/GaAs QWs agree with observed spectral peaks positions if a type-Ⅰ band line QWs is assumed. The influence of rapid thermal annealing on the quantum well transition energies is also analyzed and compared with physical models
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Keywords
砷化氮鎵, 砷化家, 電子有效質量, 光調製反射光譜, 螢光光譜
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