采用第一性原理计算从能带工程的角度设计InGaN/GaN LED电子阻挡层结构，提出了InxAl1-xN单边垒电子阻挡层这一新的概念。以半导体能带工程和外延生长动力学为重点和切入点，从物理本质上优化材料设计与生长工艺，通过调整InxAl1-xN材料组分，实现InxAl1-xN/GaN从第一类异质结（Type-I band alignment ）向第二类异质结 (Type-II band alignment)的转变。增加电子势垒的同时，着重降低空穴势垒，力争通过提高空穴注入效率，提高有源区电子复合速率，从源头上解决电子泄露问题。本项目的成功实施，不仅可以通过第二类异质结改善InGaN/GaN LED电子空穴的不匹配注入，减少电子泄露，同时对掌握InxAl1-xN三元合金材料生长动力学，揭示大注入条件下InxAl1-xN/GaN低维量子结构中电子、光子行为规律并实现有效调控具有重要意义。

Single-polar barrier for InGaN/GaN LED electron blocking layer is developed by the first-principle calculion in the view of band engineer.The band gap alignment of GaN/InxAl1-xN heterojunction change from type-I to type-II by optimization of growth parameter and specail structrue design.Therefore, the barrier for electrons increased.While the barrier for hole decreased.As a result, the asymmetric distribution of carriers in active region of InGaN/GaN LED. We argue that such kind of improvement will be benefical of eclectron-hole recombination, which can decreas the electron density in multiple quantum well.We believe that this novel single-polar barrier can be used to solove the problem of the carriers leakage in InGaN/GaN LED, especially at high injectioin density. The objective of this work is to gain a basic understanding of the behaviors of electrons and photons in low dimension GaN/InxAl1-xN systems. What's more, a potential solution will be brought out here to address the issues of efficicency droop at high current density, which is believed strongly related to electron leakage. This work will provide the scientific foundation for high efficiency InGaN/GaN LEDs.