Micro-LED器件:从极性c面到非极性或半极性的发展趋势

Micro-LED devices:the trend from polar c-plane to nonpolar or semipolar

氮化镓作为第三代照明器件材料相较于第一代硅与第二代砷化镓在性能上有了很大提高,基于氮化镓的MicroLED器件也愈发被人们所关注。然而由于在传统c面上生长的LED其自身所固有的一些缺陷往往在实际应用中发射效率不高,如存在量子限制斯塔克效应、绿色间隙、载流子传输等问题。基于非极性或半极性的LED没有极化电场,具有较强的内量子效率,电子和空穴复合机率大等优点,对非极性和半极性Micro-LED器件的研究与应用引起了人们很大的兴趣。本文对非极性和半极性Micro-LED器件研究现状进行综述。首先从量子限制斯托克效应、绿色间隙、载流子传输、效率下降4个方面介绍了非极性和半极性氮化镓基材料的优势。接着针对缺陷位错、增加光提取效率与在不同电流密度下实现全彩显示等问题,介绍了芯片成形、图案刻蚀与阵列这3种技术,最后对Micro-LED作为下一代显示引领者进行了展望。希望对Micro-LED今后的研究有所帮助。

Gallium nitride,as the third generation material of lighting devices has greatly improved,compared with the first generation of silicon and the second generation of gallium arsenide performance.Gallium nitride-based Micro-LED devices are also getting more and more attention.However,the emission efficiency of the traditional c-plane growth of LEDs is not high in practical applications,due to quantum confined stark effect,green gap,carrier transport or other problems.Nonpolar or semipolar LED has the advantages of non-polarized electric field,stronger internal quantum efficiency,and more probability of electron and hole recombination.Therefore,the research and application of nonpolar and semipolar Micro-LED devices have aroused great interest.This paper reviews the research status of nonpolar and semipolar Micro-LED devices.Firstly,the advantages of nonpolar and semipolar gallium nitride materials are introduced from four aspects:quantum confined Stark effect,green gap,carrier transport and efficiency droop.Then,three technologies of chip shaping,pattern etching and array are introduced for solving the problems of defect dislocation,low efficiency of optical extraction and realizing full color display under different current density.Finally,the prospect of Micro-LED as the next generation display leader is given.It is hoped that it will be helpful in the next research for Micro-LED.