國立臺灣大學電子工程學研究所林浩雄2006-07-262018-07-102006-07-262018-07-102005-07-31http://ntur.lib.ntu.edu.tw//handle/246246/20047本計畫包括以分子束磊晶法在砷化鎵基板上成長 銻砷化鎵/砷化鎵第二型量子井、砷化銦鎵/砷化銦 量子點結構雷射二極體的研究、以及量子點雷射動 態調變特性等研究。在第二型量子井的部分我們利 用共振腔長度調整雷射波長，並利用雷射增益的計 算來模擬銻砷化鎵/砷化鎵第二型量子井能帶排列 的關係。我們獲致的GaAs0.64Sb0.36/GaAs量子井主動 層其GaAsSb之彎曲係數為 -1.31 eV，而價電帶差與 能隙差比為1.02。在量子點雷射結構的部分，我們 發展了一種新型的耦合量子點主動層結構。與非耦 合量子點結構相比，此種結構的雷射特性並沒有劣 化，但其波長可以延長。在量子點雷射動態特性研 究的部分，我們創新提出量子點雷射之小訊號等效 電路，並且可使用P-SPICE來模擬阻抗響應與光學 響應，並且藉由與已知的雷射調變特性模擬來驗證 此模型的有效性。此外，研究量子點雷射雙能態頻 譜動態解析也是首度被實驗觀察到。激發態雷射動 作早於基態雷射行為，此與理論的模擬是一致的。The studies of this project include the molecular beam epitaxial (MBE) growth of GaAsSb type-II quantum well (QW) and InGaAs/InAs quantum dot (QD), and the modulation properties of QD laser diodes. In the first portion, GaAsSb/GaAs type-II QW lasers were fabricated. Because of the band-bending effect, the emission wavelength of the laser has a blue-shift as the cavity length is shortened. We utilized this effect to investigate the band line-up of the GaAsSb/GaAs QW. Through a simulation based on solving the Poisson and Schrödinger equations simultaneously for the band structure and optical gain of GaAsSb/GaAs QW, we found that the valence band offset ratio (Qv) of the unstrained GaAs0.64Sb0.36/GaAs is 1.02, and the unstrained band-gap bowing parameter of GaAsSb is -1.31 eV. For QD lasers, we present a novel coupled-QD structure. The structure contains two closely coupled InAs QD layers and one InGaAs capping layer on top QD layer. Cross-sectional TEM images reveal that the coupled-QDs have larger size and lower density as compared with the controlled sample. The laser of coupled-QD structure demonstrates longer emission wavelength and slightly higher threshold current density than its counterpart, which indicates the coupled-QD structure is promising for long wavelength applications. In the portion of the dynamic properties study, the small-signal equivalent circuit model of quantum-dot lasers is proposed for the first time. We use P-SPICE to simulate their impedance and optical responses. The validity of this model is confirmed by the well-known laser modulation properties. Finally, spectrally resolved dynamics of two-state lasing in QD lasers is also experimentally demonstrated for the first time in this study. The onset of excited-state lasing prior to ground-state lasing is consistent with our theoretical prediction.application/pdf466991 bytesapplication/pdfzh-TW國立臺灣大學電子工程學研究所分子束磊晶含銻化合物半導體銻砷化 鎵量子井砷化銦量子點量子點雷射彎曲係數價電帶差比調變頻寬雷射等效電路雙能態現 象molecular beam epitaxySb-based compound semiconductorGaAsSb quantum wellInAs quantum dotquantum-dot laserbowing parametervalence-band-offset ratiomodulation bandwidthlaser equivalent circuittwo-state phenomenonreporthttp://ntur.lib.ntu.edu.tw/bitstream/246246/20047/1/932215E002024.pdf