本論文旨在於架設光感應電流及電制吸收光譜量測系統，並研究長波長半導體量子井結構之光學特性。我們研究的樣品磊晶結構共有三種：對稱式量子井p-i-n雷射結構、非對稱式量子井p-i-n雷射結構和BRAQWETS n-i-n結構；利用半導體製程設備首先將晶片製作成平台型光檢測器結構後再加以量測分析。
經由BRAQWETS n-i-n結構的電制吸收光譜（Da）得知，元件在順向偏壓下受到能帶充填效應影響，於+5V的偏壓下Da峰值藍偏移約10nm，在逆向偏壓下則因量子史塔克效應，在-5V的偏壓下Da峰值紅偏移約2nm。由對稱式量子井p-i-n雷射結構光電流光譜，其e1-hh1的躍遷約在能量0.813eV（l=1.525mm）處，符合我們由光激光譜所得到的結果，在-5V的偏壓下其Da峰值紅偏移約38nm；而非對稱式量子井p-i-n雷射結構，其量子井寬度分別為15nm、10nm和5nm，由光感應電流頻譜中，可得到個別的e1-hh1躍遷能量為0.758eV（l = 1.64mm）、0.772eV（l = 1.6mm）及0.797eV（l = 1.55mm），也符合由光激光譜所得到的結果，另外在-5V的偏壓下對應於15nm量子井的e1-hh1吸收峰值紅偏移約25nm，藉由非對稱式量子井p-i-n結構的光感應電流光譜和Da光譜發現在1.25mm有一高吸收峰值，再經由量測C-V和I-V特性，確定為其n型摻雜濃度不正確所導致。

In this thesis, we have setup the measurement systems for photocurrent and electro-absorption (Da) spectroscopy, and have investigated the optical characteristics of semiconductor quantum well structures in the long wavelength regime. The measured samples are of three epi-structures including a p-i-n laser structure of the symmetric multiple quantum wells (SMQWs), a p-i-n laser structure of the asymmetric multiple quantum wells (AMQWs), and n-i-n BRAQWETS structures. The samples are fabricated in mesa type photodiode structures for the measurements.
From the Da spectrum of the n-i-n BRAQWETS structures, we observe a blue shift ~ 10nm of Da peak caused by band filling effect at +5V bias. Besides, a red shift ~ 2nm has been obtained at –5V bias caused by the quantum-confined Stark effect. The photocurrent spectrum of the SMQWs shows an e1-hh1 absorption peak at hn=0.813eV (l=1.525mm) which matches the photoluminesce spectrum. The e1-hh1 transition has a red-shift ~ 38nm at –5V bias for the SMQWs. For the AMQWs consisting of 5, 10, 15nm wells, we observe the e1-hh1 absorption peaks at 0.758eV (l=1.64mm), 0.772eV (l=1.6mm) and 0.797eV (l=1.55mm), respectively. As the AMQWs biased at –5V, a red-shift ~ 25nm is obtained for the e1-hh1 transition corresponding to the 15nm-wide wells.

目錄

第一章 緒論…………………………………………………………….1
1-1 前言………………………………………………………..1
1-2 調制光譜…………………………………………………..2
1-3 結構應用…………………………………………………..4
1-4 論文架構…………………………………………………..6

第二章 原理…………………………………………………………….7
2-1 載子躍遷…………………………………………………...7
2-1-1 躍遷機率………………………………………………...9
2-2 光電流及電制光譜………………………………………..13
2-2-1 量子侷限史塔克效應(QCSE)………………………….13
2-2-2 BRAQWETS結構………………………………………...15
2-3 透射率與吸收係數………………………………………..20
2-4 Kramers Kronig 轉換近似法……………………………22

第三章 量測系統與實驗方法…………………………………………23
3-1 量測系統簡介………………………………………………23
3-1-1 操控程式方塊圖…………………………………………26
3-2 光電流光譜量測……………………………………………27
3-3 穿透式調變量測……………………………………………30

第四章 量子井元件設計與製作………………………………………32
4-1 磊晶層結構表………………………………………………33
4-1-1 磊晶層結構之光激光譜圖………………………………39
4-2 設計概念……………………………………………………40
4-3 製程步驟……………………………………………………41
4-4 製程示意圖…………………………………………………46

第五章 結果與分析……………………………………………………50
5-1 BRAQWETS結構………………………………………………51
5-2 對稱式量子井結構…………………………………………60
5-3 非對稱式量子井結構………………………………………67

第六章 結論……………………………………………………………75

參考文獻……………………………………………………………………76
附錄A………………………………………………………………………78
附錄B………………………………………………………………………79

參考文獻

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