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氮化鎵基光電元件之特性研究 = Study on the Characteristics of GaN-Based Optoelectronic Devices / 吳嘉祥.

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摘要註

本研究旨在探討藍光發光二極體（Blue Light Emitting Diode, 簡稱藍光LED）在模擬不同溫度的工作環境下，調整驅動電流的電致發光特性，觀察其電流對藍光LED的影響。透過控制電流變化(5mA至140mA)並調整環境溫度變化(10K至300K)，分析其光學特性變化，包括光譜峰值位置、發光峰值能量、發光強度及半高寬（FWHM）。 經實驗結果發現，發光峰值能量隨著電流逐漸增加呈現上升趨勢，發光波長藍移的現象，主要受到局域態填充、能帶填充效應與QCSE的屏蔽效應的聯合影響。但當高電流注入後，高載子濃度所造成的載子溢出與QCSE的屏蔽效應減弱，使發光峰值能量逐漸縮小，發光波長紅移的現象。而在環境溫度提升及高電流注入所產生的自熱效應，促使晶格振動更加劇烈，使載子與聲子散射增強，溫度提升也會使晶格熱膨脹，進而導致發光波長紅移。而在半高寬(FWHM)的結果中，在低電流範圍下載子被侷限在局域態進行輻射復合，能量分佈較為集中，FWHM較窄。而在高電流及高溫的環境下，載子與聲子散射、載子與載子散射作用加強，導致能量分佈變廣，FWHM增加。在發光強度的分析結果顯示，發光強度隨著電流增加而提升，隨後逐漸趨緩。一開始載子能夠有效侷限於量子阱內進行高效率的輻射復合，而在高電流及自熱效應的影響，會發生載子溢出及歐傑復合，造成發光強度受到限制，甚至出現效率下降的現象。 從實驗結果顯示，藍光LED的發光特性會因為電流及環境溫度的改變而產生不同的變化。因此深入理解載子動態與發光機制，有助於未來提升藍光LED元件的效率與可靠性，對於照明及顯示技術的發展具有參考價值。. This study investigates the electroluminescence characteristics of blue light-emitting diodes (Blue LEDs) under various simulated operating temper-atures and different driving currents. By varying the injection current from 5 mA to 140 mA and adjusting the ambient temperature from 10 K to 300 K, the optical properties such as peak wavelength, emission peak energy, intensity, and full width at half maximum (FWHM) were systematically analyzed. Experimental results show that the emission peak energy initially in-creases with rising current, resulting in a blue-shifted emission spectrum. This behavior is primarily attributed to the combined effects of localized state filling, band-filling effects, and the screening of the quantum-confined Stark effect (QCSE). However, at higher injection currents, the carrier overflow and re-duced QCSE screening lead to a decrease in emission peak energy and a red-shift in the emission wavelength. Additionally, elevated temperatures and self-heating at high currents enhance lattice vibrations and carrier-phonon in-teractions, causing further red-shift due to increased phonon scattering and thermal expansion. In terms of FWHM, a narrower spectral width is observed at low currents, indicating more localized radiative recombination. At higher currents and temperatures, stronger carrier-phonon and carrier-carrier scattering broaden the energy distribution, resulting in increased FWHM. The emission intensity ini-tially rises with increasing current but gradually saturates under high current injection due to carrier overflow and Auger recombination, eventually leading to efficiency degradation. Overall, the emission characteristics of blue LEDs are significantly in-fluenced by changes in current and temperature. A better understanding of the underlying carrier dynamics and emission mechanisms is crucial for enhancing the efficiency and reliability of blue LED devices, and serves as a valuable reference for the development of future ligh

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