Modification of the Optical Polarization in High Al-Content AlGaN

相比于传统紫外光源（如汞灯和氙灯），AlGaN半导体紫外光电子器件具有无汞污染、波长可调、体积小、集成性好、耐高温、抗辐射以及能耗低、寿命长等优点，在工业、农业、国防和医疗卫生等领域都有着广阔的应用前景和巨大的市场需求。然而，由于高Al组分AlGaN材料中存在诸多问题，例如外延生长困难、p型掺杂率低、发光偏振特性独特等等，导致深紫外波段器件的发光效率普遍较低，制约了深紫外发光器件的发展与应用。本论文采用第一性原理的计算模拟方法，围绕AlGaN材料中的光学偏振特性及其调控开展了系统的研究工作，以探索提高高Al组分AlGaN材料带边跃迁光发射沿c轴方向传播比率的新途径。具体的研究工作如下： 首先...Due to the advantages of mercury free, tunable wavelength, small volume, good integrity, high temperature and radiation resistance, low energy consumption and long life, etc, the Al-rich AlGaN semiconductor optoelectronic devices semiconductor devices have a wide variety of potential applications and great market demand in industry, agriculture, national defense and health and other fields. Howeve...学位：理学硕士院系专业：物理科学与技术学院_凝聚态物理学号：1982013115296

Emission Mechanism of High Al-content AlGaN Multiple Quantum Wells

紫外LED的发光功率和效率还远不能令人们满意,波长短于300 nm的深紫外LED的发光效率普遍较低。厘清高Al组分Al Ga N多量子阱结构的发光机制将有利于探索改善深紫外LED的发光效率的新途径、新方法。为此,本文通过金属有机气相外延技术外延生长了表面平整、界面清晰可辨且陡峭的高Al组分AlGa N多量子阱结构材料,并对其进行变温光致发光谱测试,结合数值计算,深入探讨了Al Ga N量子阱的发光机制。研究表明,量子阱中具有很强的局域化效应,其发光和局域激子的跳跃息息相关,而发光的猝灭则与局域激子的解局域以及位错引起的非辐射复合有关。The quantum efficiency of deep UV light emitting diodes( LED) drops dramatically with the increasing of Al content. Understanding the emission mechanism of high Al-content Al Ga N multiple quantum wells( MQW) is the one of the most important objects for improving the quantum efficiency of deep UV LED. In this work,high Al-content Al Ga N MQW structure with atomically flat hetero-interfaces was grown and characterized by photoluminescence( PL) measurements at different temperatures. The results indicate that there is a strong exciton-localization effect in the MQW structure and the emission is closely related to the hopping of the excitons. Due to the exciton delocalization and nonradiative recombination at defects,the PL intensity is strongly quenched at high temperatures.“973”国家重点基础研究发展计划(2012CB619300);; “863”国家高技术研究发展计划(2014AA032608);; 国家自然科学基金(U1405253;61227009;11204254;11404271);; 福建省自然科学基金(2015J01028)资助项

Roots of competency, setbacks and hardship, and growth opportunities─Clinical Nursing Practice of New Nursing Students

[[abstract]]背景：護理系學生實際接觸臨床實務的基本護理學與實習課程是銜接各護理核心科目實習之重要基礎。 目的：為能提升教學成效，期望透過學生學習之回饋中，明瞭學生實習之經驗，以做為教學精進之參考。 方法：採質性研究焦點團體訪談法，以半結構式訪談指引進行深入訪談。研究對象以技職體系某大學護理系已完成基本護理學實習學生為對象，以隨機抽樣方式進行招募，共有40 位學生參與訪談。 結果：研究結果經分析後共歸納出三大主題，包括：一、能力的紮根，二、挫折困頓的經驗，三、成長的歷程等；其中涵蓋有十一個次主題。結論：從門外漢至新手護生的實習經驗中，真實反應學生的心境，其中包含正向與負向經驗。學生之專業能力紮根的過程中，經歷挫折、困頓，嘗試運用自我調整的模式，學習如何因應多變化的實習情境。針對學生正負向學習經驗的轉化，須仰賴實習教師們的敏感度及同理心，深入瞭解及評估學生在初次實習之壓力情境與感受，並能識別學生個別狀態，運用不同的教學策略，因材施教。 實務應用：研究結果提供學生實際臨床實習經驗、對實務的看法以及教學輔導方式的體驗，可以作為未來護理教育中臨床教學方法改進之參考

Selecting Methods and Awaiting Growth: The Teaching Experience of Fundamental Nursing Practicum Instructors

[[abstract]]背　景 基本護理學實習是護理專業的入門及基礎，多重因素影響護生臨床實習成效；其中實習教師是整體教學計劃的規劃與執行者，其所採行的教學方法、策略與教學態度極為關鍵。因此透過教師教學的反思，瞭解基本護理實習的教學特性，將有助於實習教師協助學生開發個人潛能，做為專業發展的基石。 目　的 從基本護理學實習教師觀點，探討基本護理臨床實習之教學特質。 方　法 本研究採質性研究法，研究對象為輔導技職院校科技大學四年制護理系基本護理實習之實習教師。資料收集的時間為基本護理實習期間，共進行五次焦點團體會議討論，每次時間約二至四小時。焦點團體主持人為研究主持人，針對學生學習表現，實習教學設計、教學經驗分享等議題，引導老師分享對學生學習表現的觀察與指導經驗，再以內容分析法進行資料分析。 結　果 實習教師所展現之基本護理臨床實習教學特質，共有三大主題，分別為需瞭解學生特質的「新手上路狀況多，慢慢行」，教師對於學生的「能力、心情與困擾需洞悉」，以及教學特質上應展現的「鼓勵支持中選擇方法」。 結　論／實務應用 基本護理實習教師需能了解學生學習特性，運用合宜的教學方法、策略與態度來進行輔導；而過程中，實習單位人員、環境的準備等均是使學生能有良好學習經驗不可或缺的要素。本研究結果，可提供帶領技職院校科技大學護理系基本護理學實習教師教學準備之參考。 Background: A constellation of factors accounts for teaching efficacy in the fundamental nursing practicum. Teachers play a critical role in terms of designing and executing an appropriate teaching plan, choosing effective methods, and holding appropriate teaching attitudes. It is thus extremely important that clinical teachers master the core characteristics of basic nursing practice. Purpose: This study aimed to illuminate the core characteristics of basic nursing practice for students for reference by clinical practicum teachers. Methods: Qualitative research was used to identify the fundamentals of nursing practice by clinical teacher. Five focus group meetings were convened during the practice period. The researchers presided over group discussions held during the normal weekly teaching schedule and lasting approximately 2-4 hours each. The content analysis was adopted to analyze the data. Results: Three major themes were proposed, including (1) student status: “novices were stymied by problems and thus improved slowly”; (2) teacher awareness: “teachers need to be aware of student capabilities, mood, and discomfort”; and (3) teaching style: “a good choice of methods should support and encourage students. Conclusions / Implications for Practice: To cultivate professional nursing knowledge and self-confidence for future professional commitment, clinical teachers must first understand the characteristics and motivations of learning of their students and then select the, skills, and attitudes appropriate to provide step-by-step guidance. Communication with staffs and the preparation of atmosphere prior to nursing practice are also essential for students. Results provide insights into the technical college environment with regard to basic-level clinical nursing practice