電激發光子晶體面射型雷射之研究

Abstract

於本篇論文中，我們實現氧化銦錫(ITO)作為透明導電披覆層取代了傳統的披覆層並且二維光子晶體結構成功的實現光子晶體面射型雷射，光子晶體的週期設計為265nm、275nm與285nm三種，並展現三種不同波長以及三種不同面積的雷射操作來進行進一步的探討。本實驗的砷化鎵樣品以分子束磊晶系統(MBE)所製作，其中包含三層的砷化銦銦(InGaAs)量子井。本篇論文中不再以劈裂元件來製造鏡面增加反射率，而採用另一種方式，利用大面積光子晶體來產生出面射型的雷射。在完成之後，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。於本次實驗中製作出最低閾值電流密度為0.94 kA/cm2，三種波長位於900nm、927nm與955nm附近的面射型雷射。我們量測光晶面積100 µm*100 µm週期275 nm元件的遠場，測出發散角是2.1度，並同樣用這一個元件量測出二維光子晶體的能帶圖。本篇論文成功建立一套針對面射型雷射的穩定製作程序，大大簡化光子晶體面射型雷射的製程，不再需要再次磊晶或是高溫接合的製程，也可以實現良好的雷射特性。

In this thesis, we successfully use two dimensional photonic crystals to realize surface emitting lasers without cleaved facet covered with Indium Tin Oxide (ITO) to replace the conventional cladding layer. The photonic crystal surface emitting lasers (PCSELs) are designed to have there kinds of periods and cavity areas. The wafers used in the experiment were epitaxially grown by molecular beam epitaxy (MBE), including 3 pairs of InGaAs quantum wells. In this work, the cleaved facet is no longer required as mirrors to increase reflectivity. Instead, large areas of photonic crystal facilite laser feedback and produce surafece emitting laser. The laser performance such as L-I-V curves, operation at different temperatures and near/far field images are discussed. The low threshold current density of 0.94 kA/cm2 is realized and laser can be operated above 343K. Lasing peaks locate at 899 nm, 927 nm and 958 nm corresponding to lattice constants of 265 nm, 275 nm, and 285 nm. The divergence angle of PCSEL is 2.1° from the far field measurement. The band structures are successfully measured below and above threshold current. We successfully demonstrate and establish a stable manufacturing process of PCSELs without wafer fusion and regrowth.