臺灣大學: 電子工程學研究所林浩雄朱讓宣Chu, Jang-HsuanJang-HsuanChu2013-04-102018-07-102013-04-102018-07-102010http://ntur.lib.ntu.edu.tw//handle/246246/257032本論文使用氣態源分子束磊晶機成長砷化銦量子點結合銻砷化鎵/砷化鎵(銻成分30%)第二型量子井複合雷射元件，我們發現增加了量子點的複合結構，可以降低起振電流密度以及內部損耗，並提高內部量子效率、模態增益以及特徵溫度。我們認為元件特性的改善是由於在量子點內的電洞會穿隧到量子井，形成帶電荷的量子點將在量子點與量子井間產生位能波動，使得躍遷矩陣元素增加造成上述的結果；另外我們將複合結構中銻砷化鎵量子井的銻含量從原來的30%增加到34%，結果雖然會使得雷射元件放光波長由1200 nm略為延伸到1206 nm，但雷射元件的內部量子效率降低、起振電流和內部損耗增加、雷射的增益下降。我們再從雷射元件的室溫PL量測其個別的半高寬，發現銻含量從30%增加到34%時，其半高寬從94 nm擴大到113 nm，可能銻含量的增加造成量子井與量子點間位能波動的改變，使得雷射元件效能變差。In this study, GaAs0.7Sb0.3/GaAs type-II quantum well lasers with an adjacent InAs quantum dot layer have been fabricated by gas-source molecular beam epitaxy. We found that the composite structure can decrease the threshold current density and the internal loss, and enhance the internal quantum efficiency, modal gain and characteristic temperature. We believe that the hole in quantum dots will tunnel into the quantum well, and the charged quantum dots could result in a potential fluctuation between the quantum dots and quantum well. The local confinement resulting from the potential fluctuation enhances the optical transition element, resulting in the aforementioned good performances. Increasing the Sb content of the composite structure from 30% to 34% makes the laser emission wavelength slightly red shift from 1200 nm to 1206 nm. However, the quality of GaAsSb quantum well becomes worse. From the room temperature PL of the laser samples, we found that the FWHM broadens from 93 nm to 113 nm when the Sb content increases from 30% to 34%, indicating the change of potential fluctuation between the quantum well and quantum dot. This change could result in the degradation of laser performances.1794410 bytesapplication/pdfen-US量子點量子井銻砷化鎵第二型雷射quantum dotquantum wellGaAsSbtype-IIlaserthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/257032/1/ntu-99-R96943087-1.pdf