本論文提出以一特異人造晶格結構”量子結構晶格”為主幹之光電元件研究，並已成功在氮化鎵/氮化銦鎵異質結構上製作出量子結構晶格及相關光電元件。首先，使用時域有限差分法之模擬方式，模擬出氮化鎵/氮化銦鎵單層量子井和量子結構晶格之輻射場圖。模擬結果顯示，藉由設計量子結構晶格之晶格週期，可以改變氮化鎵/氮化銦鎵結構發射頻譜之輻射場圖，且在低階布拉格繞射模態下，具有較佳之光聚束效果。其次，開發軟性奈米壓印技術以製作晶圓尺寸級之週期性奈米結構，其原理為使用一透明高分子材料”聚二甲基矽氧甲烷”作為模具，並將奈米圖案透過翻模之過程，將圖案資訊從矽母片轉印至模具上，而後，將模具壓印於已塗佈奈米光阻之樣品上，並使用汞燈進行光阻固化，即完成奈米圖案之轉印。實驗結果證明，此技術已可在兩吋之矽晶圓上達到全面均勻之奈米圖案。
本研究使用軟性奈米壓印技術於氮化鎵/氮化銦鎵結構上製作量子結構晶格。從模擬與實驗結果皆證實，製作量子結構晶格之樣品具有較窄之輻射場圖。且藉由改變量子結構晶格的週期或氮化銦鎵之銦含量，可以控制樣品發射頻譜之波長與輻射場圖。此外，量子井所產生的光會在薄膜間多重反射，而在光致發光頻譜中產生數個干涉峰。為了消除此干涉效應，本研究發展出以半經驗頻譜干涉法消除氮化鎵薄膜與藍寶石基板間的干涉效應，其原理為使用薄膜間干涉效應所產生之多重峰波長位置，帶入餘弦方程式，進而推導出相對應之特性干涉方程式，並利用矩陣實驗室(Matlab)之軟體，繪製出干涉頻譜，以消除原始頻譜中的干涉效應。實驗結果證實，此方法為一快速且簡易之干涉頻譜校正方式。
最後，本研究已成功將氮化鎵/氮化銦鎵量子結構晶格製作於發光二極體中，並提出三種不同製程方式之量子結構晶格發光二極體，其中包含蝕刻結合二次磊晶、離子佈植結合二次磊晶和離子佈植等三種製作方式。實驗結果顯示，在主動區製作量子結構晶格元件之電致發光頻譜具有光聚束之效果，且蝕刻結合二次磊晶與離子佈植所製成之元件的輻射場圖皆在發散角度10°內具有較佳之聚束效果。

In this dissertation, an artificial structure “Quantum Structure Lattice (QSL)” fabricated on InGaN/GaN quantum well (QW) heterostructure has been demonstrated. At first, the numerical analysis method “finite-difference time-domain (FDTD)” is employed to simulate the radiation pattern of bulk single quantum well (SQW) and QSL arrays embedded in SQW. The simulation results illustrate that the QSL arrays with appropriate design has potential to control the surface radiation pattern of the structure. Furthermore, collimated radiation pattern can be observed clearly in QSL array that fulfills lower orders of Bragg diffraction condition. Second, QSL array fabrication process over whole wafer has been achieved using soft nanoimprint lithography (soft-NIL). The soft-NIL process was realized by employing a transparent polydimethylsiloxane (PDMS) mold to transfer nano-patterns into the substrate by deforming the photoresist coated substrate surface and cured by employing an ultra-violate light. The experiment results show that the soft-NIL works well to transfer ultra-uniform nano-pattern onto 2” substrates.
The well-developed soft-NIL is used to fabricate QSL arrays from the active region of the GaN/InGaN heterostructure. The photoluminescence (PL) measurements illustrate that the QSL array has the ability to control the radiation pattern of the spontaneous emission, and the experimental results are verified by the FDTD simulations.
In PL measurements of GaN-on-sapphire structures, multiple peaks in PL spectrum are commonly observed, which causes ambiguity in interpreting the real PL peak position. This is caused by multiple light reflections in air/(In)GaN/Sapphire thin layer structures. In order to extract the correct emission peak from the measured PL spectrum, a semi-empirical method has been developed to eliminate the interference (Fabry-Perot) effect. Using three selected interference peaks in the measured PL spectrum to deduce the interference function (IF) of the thin layer structure, the corrected spectrum can be derived. The experiment results illustrate that the semi-empirical method is a fast and simple way to correct the distorted PL spectrum caused by multilayer interference.
Finally, QSL arrays are integrated into the active region of multiple quantum wells light emitting diode (LED) structures. Three different QSL fabrication methods are proposed, which include GaN regrowth after reactive-ion etching (RIE) etching, GaN regrowth after ion-implantation, and direct ion-implantation techniques. Electroluminescence (EL) spectra illustrate that QSL MQW-LEDs show collimated characteristic radiation patterns similar to those from a single QSL array heterostructure.

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