有鑒於目前成長於 (0001) 極性晶面之氮化鎵材料發光二極體，因為壓電場產生的量子侷限史塔克效應 ( quantum confined Stark effect, QCSE )而影響量子井的發光效率，非極性或半極性晶面發光二極體已成了眾人鑽研的課題。在本論文中，我們利用條狀側向磊晶成長方式在(0001)藍寶石基板上成長半極性發光二極體結構，並且成功製備半極性發光二極體。此法不但能利用低成本的藍寶石基板獲得半極性發光二極體，同時亦可利用側向磊晶成長機制有效的降低缺陷密度，提高內部量子效率。 在本研究中，我們分別製備了{1-101}晶面及{11-22}晶面半極性InGaN/GaN多層量子井及發光二極體，希望比較不同半極性晶面量子井中的壓電性電場。由光激發光譜及電激發光譜分析發現，與(0001)晶面相較，{1-101}和{11-22}半極性晶面發光二極體光譜波峰隨激發強度的變化都是較少的，顯示{1-101}和{11-22}量子井中的內建電場相較於(0001)確實是比較小。實驗顯示在高電流操作下，{11-22}晶面半極性發光二極體的發光效率，顯示其未來是頗具發展淺力的。 Currently commercially available GaN light-emitting diodes (LEDs) are fabricated on the strongly polarized c-plan wurtzite crystal. The internal quantum efficiency has been limited by the Quantum Confined Stark Effect. The growth of non-polar and semi-polar III–nitride materials has therefore attracted great attention in recent years. In this work, stripe patterns with semipolar side facets are obtained by lateral overgrowth on c-plane sapphire substrates using metal-organic chemical vapor deposition. Semi-polar LEDs are also demonstrated. This selective overgrowth technique offers the advantages of reduced dislocations as well as lower internal piezoelectric field. InGaN/GaN multiple quantum well LEDs on the semi-polar {1-101} and {11-22} side facets are characterized by photoluminescence (PL) and electroluminescence (EL). Compared to the c-plane LEDs, the luminescence of both semi-polar LEDs shows less dependence on injecting current or exaction power, indicating their lower internal electric field. Besides, the {11-22} semi-polar LEDs exhibit higher internal quantum efficiency under high current injection, manifesting itself a good candidate for high efficiency LEDs.
