本論文研究主旨為提升非對稱性量子點(AMQD)太陽能電池轉換效率。樣品
來源為利用實驗室分子束磊晶(MBE)儀器於砷化鎵基板上成長非對稱性量子點
結構。為了提升樣品的光伏特效應，我們引入量子井以及井內調變摻雜結構來探
討應力以及內建電場所造成的影響。
實驗分析上，我們利用光激螢光量測系統分析非對稱性量子點結構的光學性
質，接著將量測結果作 Gaussian fitting 來分析非對稱性量子點的發光特性。此外，
我們更利用量測光電流、外部量子效率、電致吸收、電調制反射光譜對磊晶結構
加以分析比對，並且在太陽光照度為 AM1.5 下得到光伏特基本參數。
由分析結果發現，量子點結構能有效地藉由吸收額外的光子來提升光電流，
然而成長量子點後所殘留的應力會導致開路電壓嚴重的損失。為了減緩應力所造
成的晶格缺陷並且增加載子的汲取，我們引入成長溫度不同的量子井結構，以及
在量子井內進行不同類型的摻雜。由數據分析顯示，高溫成長的量子井結構可有
效提升磊晶品質，減少非輻射性的複合，以及高濃度的 p 型摻雜有效提升光電流
的萃取。由上述改善磊晶品質過程,轉換效率得以超越砷化鎵基板的轉換效率。
除此之外，我們更藉由適度的表面濕蝕刻使樣品減少表面性的複合，以及將電極
圖形最佳化得到了一個最佳的轉換效率 V OC = 0.74 V，J SC = 18.82 mA/cm
2 ，FF = 0.78，η = 10.86% 。

The purpose of the thesis is enhancing efficiency of asymmetric quantum dots
(AMQD) solar cells. The AMQD structures are grown on the n-type GaAs substrate
by (MBE). In order to enhance the photovoltaic characteristics, we introduce InGaAs
quantum well (QW) and modulation doping in the well to investigate effect of the
strain relief and built-in electric field in the active layer.
In our experiment, we analyze the optical property of AMQD structures by
photoluminescence measurement system, and then decompose emission wavelength
by Gaussian fitting to find optical characteristics of each single layer quantum dots.
Besides, we also measure photocurrent spectra, external quantum efficiency, electrical
absorption, and electro reflectance spectra to discuss carrier transition inside AMQD
structure . Finally, we acquire the photovoltaic basic parameter under one sun.
The results show that QDs provide additional photocurrent via absorbing extra
photons, but the open circuit voltage decrease seriously due to the accumulated strains.
So as to relieve the strains and enhance carriers extraction, we introduce QW layers
with different growth temperatures and change the modulation doping concentrations .
From the results, the higher growth temperature for QW diminishes accumulated
strains, and the higher p-type modulation doping concentration indicates an
extraction enhancement due to the stronger built-in electric field. By optimizing QW
growth conditions, the efficiency has overtaken GaAs baseline cells. In addition, we
improve the photon-excited current collection by using matrix pattern and wet etching
on the device surface, the best photovoltaic characteristic shows V OC = 0.74 V, J SC =
18.82 mA/cm2, FF = 0.78, η= 10.86%.

論文審定書............................................................................................................... i
誌謝............................................................................................................................. iii
中文摘要......................................................................................................................iv
英文摘要....................................................................................................................... v
第一章 緒論................................................................................................................. 1
1-1 前言 ............................................................................................................. 1
1-2 Ⅲ-Ⅴ族量子點太陽電池 ............................................................................ 1
1-3 實驗動機 ..................................................................................................... 3
第二章 實驗樣品與介紹............................................................................................. 5
2-1 寬波段量子點太陽電池結構 ..................................................................... 5
第三章 量測系統與架構........................................................................................... 10
3-1 光激螢光量測 ........................................................................................... 10
3-2 電調制反射光譜量測 ............................................................................... 11
3-3 電致螢光量測 ........................................................................................... 12
3-4 光電流量測 ............................................................................................... 13
3-5 電致吸收量測 ........................................................................................... 15
3-6 量測元件 mesa 製程步驟 ......................................................................... 16
第四章 實驗結果與分析........................................................................................... 21
4-1 螢光光譜比較與分析 ............................................................................... 21
4-2 元件光譜吸收分析 ................................................................................... 39
4-3 外部量子效率(EQE) ................................................................................. 55
4-5 照光 I-V curve 量測 .................................................................................. 58

第五章 結論............................................................................................................... 67
參考文獻 .................................................................................................................... 69

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