InAlGaN在藍紫光半導體雷射和紫外光發光二極體的模擬研究

Abstract

摘 要 在本論文中嘗試在半導體雷射結構In0.1Ga0.9N/In0.02Ga0.98N，發光波長落在405nm，使用四元化合物InAlGaN，取代一般的三元化合物AlGaN當作電子阻擋層(blocking layer)，並且讓四元化合物InAlGAN中Al:In比例為5：1，使其對GaN晶格匹配。模擬的結果發現，以四元化合物InAlGaN當作電子阻擋層，可以比一般使用三元化合物AlGaN當作阻擋層，得到更低的臨界電流值。 我們建議使用四元化合物InAlGaN當作電子阻擋層，鋁的含量在20%-35%時，可以將特性溫度(characteristic temperature,T0)維持在134K-140K，雖然略低於使用三元化合物的特性溫度(147K)，但是整體的輸出表現優於使用三元化合物，顯示出使用InAlGaN材料當作電子阻擋層的好處。在本論文的結構下，模擬得到最好的輸出特性為使用In0.05Al0.25Ga0.7N作為電子阻擋層。 另外我們亦嘗試建立使用InAlGaN作為LED主動層發光的架構，發光的波長在368nm左右，目前模擬的結果和實際元件發光的特性相符，對於不同結構設計所影響的輸出特性，例如變化不同的量子井數目，和電子阻擋層結構影響的分析，也做了一些比較和討論。

Abstract The In0.1Ga0.9N/In0.02Ga0.98N LD structures using quaternary InAlGaN with variant Al and In compositions as electronic blocking layers are numerically investigated. Varying the aluminum (Al) composition in InAlGaN electronic blocking layer with a fixed indium (In) value (Al:In=5:1) indicates that lower threshold current and higher characteristic temperature (T0) value can be obtained when the Al compositions in InAlGaN are 20%-35%. The results indicate that using quaternary InAlGaN provides lower threshold current but lower T0 value than conventional Al0.2Ga0.8N electronic blocking layer. We also construct 368nm LED structure using quaternary InAlGaN as active region by simulation. The simulation results fit experiment characteristics very well. Base on agreement of experiment characteristics to simulation results, we also numerically investigate by using different number of quantum wells and different electronic blocking layer structures to discuss output characteristic changes. The results indicate that although more quantum wells and electronic blocking layer with enough Al composition can suppress leakage current from high temperature. But output power loss is still large as temperature increasing.