量子井紅外線偵測器之光偶合效應研究

Abstract

在本篇論文中，主要探討8-10μm波段的量子井紅外線偵測器(QWIP)之基本特性、製程與量測，並對光在QWIP元件中的偶合效應做更深入的研究。一方面我們設計了光罩，以不同邊緣長度元件的量測結果來證實平台邊緣偶合效應的存在及其重要性。以我們尺寸200μm*200μm的元件而言，平台邊緣偶合對光電流的貢獻佔了25%，此效應的存在，可以對於沒有光柵偶合的元件之反應度的存在，提出一項重要的解釋與實驗證明，而且尺寸越小的元件，此偶合效應的貢獻比例越大(以40μm*40μm大小的元件來說，此效應貢獻了62%的光電流)，應用於小尺寸元件的設計製造上，有相當大的幫助。 另一方面，我們對於量子井結構吸收光的原理亦做一闡釋，我們的實驗間接證明了量子井可以吸收TE mode的光(不經偶合效應)，可提供往後在這方面的研究一個參考。

In this thesis, we have studied 8-10 μm band quantum well infrared photodetectors (QWIPs), including the basic theory, the experimental techniques, and the further study of optical coupling effect. We designed a mask with various mesa edge lengths and get the result to prove the significance of the mesa edge coupling effect. In our device (size 200μm*200μm)，the contribution of the mesa edge coupling is 25%. By the proof of the effect, we could explain the response of the device without grating coupling. Besides, the smaller our device is, the more this coupling effect contributes. For 40μm*40μm devices, this coupling effect contributes 62% photocurrent. It would be very useful in the application and fabrication of the small QWIP devices. On the other hand, we described and derived the mechanism of the absorption by quantum well structure. Our experimental result also supported that the TE mode infrared light is absorbed by the quantum well structure (without any coupling). We think it could give a reference in the future research.