採用氧化銦錫作透明導電披覆層之砷化銦量子點分布回饋式面射型雷射之特性研究

Abstract

於本篇論文中，我們以氧化銦錫(ITO)作為透明導電披覆層取代了傳統的披覆層並且成功的製作出量子點(QD)分布回饋式(DFB)的面射型雷射，也針對其雷射特性作相關的研究與探討。本實驗的砷化鎵樣品以分子束磊晶系統(MBE)所製作，其中包含七層的砷化銦(InAs)量子點，發光波段位於900nm至1400nm之間。分布式回饋(DFB)的週期設計為350nm與375nm兩種，空氣隙縫大小約為100nm。不同以往的是，本篇論文中以氧化銦錫作為透明導電披覆層有效的簡化了複雜的製作程序並提高樣品良率。在完成之後，我們以脈衝的方式對元件的雷射特性進行量測，包括LIV特性、變溫及近遠場的實驗結果，同時以商用軟體COMSOL分析並進行探討。最後的結果中，我們於本次實驗中製作出閾值電流密度210 A/cm2，發光波長位於1298nm附近的分布回饋式的面射型雷射。此元件擁有沿著光柵結構的發散角<1o，操作溫度高於室溫323K等優良的特性。本篇論文成功建立一套針對面射型雷射的穩定製作程序，於未來更可進一步將其應用到不同材料，如：氮化鎵、銻化鎵等光子晶體面射型雷射的元件上，相信此結果對於光子晶體雷射的發展上會有很進一步的貢獻。

In this thesis, we successfully demonstrate a surface emitting distributed feedback (DFB) InAs quantum dot laser with the conventional cladding layer replaced with ITO. The laser characteristics were measured and analyzed. The wafers used in the experiment were epitaxially grown by molecular beam epitaxy (MBE), including 7 pairs of InAs quantum dots with spontaneous emission covering 900nm-1400nm. The period of grating is designed to be 350nm/375nm and the void gaps are around 100nm. There is a notably difference in this experiment, with the ITO as the transparent conducting cladding, we effectively simplify the manufacturing process of conventional DFB lasers and improve the yield-rate simultaneously. The laser performance such as L-I-V curve, operation at different temperatures and near/far field images are also shown in this thesis. The threshold current density is 210 A/cm2, lasing peak locates at 1298nm and the far field divergence angle <1o. The laser with various benefits can be operated above 323K. In addition, the experimental results are consistent with the simulation results calculated by COMSOL. In this thesis, we successfully demonstrate and establish a stable manufacturing process of DFB lasers; furthermore, it is feasible to apply the fabrication method to the photonic crystal surface emitting lasers (PCSEL) based on different materials such as GaN and GaSb etc. It might be a tremendous contribution to the development of PCSEL.