量子點與量子環紅外線偵測器之光電特性

The Opto-electronic Properties of Quantum Dot and Quantum Ring Infrared Photodetector

林億龍(Yi-Lung Lin)

指導教授 ： 李嗣涔

國立臺灣大學/電機資訊學院/電子工程學研究所/碩士(2006年)

https://doi.org/10.6342/NTU.2006.00799

摘要

ㄧ個砷化銦量子點高度較小的量子點紅外線偵測器被發現具有不尋常的極化相關頻譜響應。由於高度較小，每一個量子點會承受較大垂直電場，此電場會讓垂直方向的電子能帶產生極大扭曲，使得在s極化光照射下，電子從基態躍遷到導電帶的機率增加，因此造成s極化光的頻譜響應變大。此外增加砷化鎵空間層厚度，可以減少量子點紅外線偵測器的暗電流，進而提高背景限制溫度。另外藉由將2.5 ML砷化銦量子點部份覆蓋砷化鎵後進行退火可以形成銦砷化鎵量子環結構。與2.5 ML砷化銦量子點比較，銦砷化鎵量子環的光激放光頻譜峰值會藍移。此現象是由於銦砷化鎵具有較大的能障及量子環高度較小所致。最後，採用銦砷化鎵量子環結構的紅外線偵測器被成功製作出來。此種量子環紅外線偵測器的特性亦被完整研究。

關鍵字

量子點 ； 量子環 ； 紅外線偵測器

並列摘要

A quantum dot infrared photodetector (QDIP) with smaller dot height of InAs quantum dots (QDs) is found exhibiting unusual polarization dependence in spectral responses. Due to smaller dot height, every QD in this QDIP averagely shares larger vertical electric field, which creates very large band-bending on the vertical-confined electron band-diagram. Under this large band-bending, the transition probability of electrons from ground to conduction band under s-polarized light increases and this causes larger spectral response of s-polarized light. Besides, by increasing the GaAs spacer thickness, the dark current of QDIP can be reduced and thus improving background limited performance (BLIP) temperature. In addition, the InGaAs quantum rings (QRs) are formed by partially capping GaAs on 2.5 ML InAs QDs and then annealing. Compared with 2.5 ML InAs QD structure, PL peak blue-shift is observed for the QR structure. This phenomenon is attributed to a larger bandgap of the InGaAs material and a smaller QR rim height. Finally, infrared photodetectors employ InGaAs QR structure (QRIPs) are successfully fabricated, and their characteristics are completely investigated.

並列關鍵字

quantum dot ； quantum ring ； infrared photodetector

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