光激發式垂直外腔面射型量子點雷射之研製

Abstract

本論文研製光激發式垂直外腔面射型量子點半導體雷射，我們採用的方法係將完整的垂直腔面射型雷射利用蝕刻方式，試圖去除上半部布拉格反射鏡，製作成只有增益介質與單邊布拉格反射鏡的元件;蝕刻方式則分為濕式與乾式兩種。 在濕式蝕刻方面，由於試片中的階梯型磊晶結構，使得選擇性蝕刻效果不佳，但在非選擇性蝕刻方面，我們則是成功地建立了可精準地控制蝕刻深度的光學系統，以及其數學模擬程式，成功地將試片蝕刻至目標表面。 為了追求試片表面的平整度，我們則是利用多次乾式蝕刻製程，亦成功地將試片蝕刻至目標結構，另外，在乾式蝕刻過程中，無預期下產生了微米柱雷射，故本論文也會探討其產生原因以及分析其光學特性。 我們將經過製程過後的元件量測其發光特性、光譜與反射率等，並且我們亦架設了光激發外腔式雷射系統，然而實驗結果並沒有達到足夠增益而產生雷射，我們認為元件結構將會是一個重要的因素，特別是最表面幾層的厚度影響較深，故也針對了不同表面結構與抗反射層厚度所形成的內部共振腔效應做模擬計算。

In this thesis, we have fabricated optically pumped vertical-external-cavity surface emitting quantum dot Laser. Unlike the method generally used to fabricate epitaxial VECSEL device, etching process was utilized among the process of fabricating the VECSEL device. We have carried out both wet-etching and dry-etching process. And we use two methods in wet-etching process: selective wet-etching and unselective wet -etching. The selective wet-etching was not recommended in the case of gradient epitaxial structure due to on account of causing the damage on the surface. In terms of unselective wet-etching process, we successfully demonstrate an optical system. We can use the system and our simulation to control the precise etch depth to expose the target layer. On the other hands, we also can use dry-etching process to fabricate the device. And we accidentally observe the micro-Pillar laser in dry-etching process. The devices are then taken under a series of measurements, including optical characteristics, optical spectrum, and reflectance spectrum. To study the optically pumped VECSEL, we built an external cavity system and tried several methods by changing the external cavity setup, but the result did not reach lasing. We consider that the device surface structure is an important issue. Therefore, the simulation was presented in this study.