Nonpolar and semipolar III-nitride-based blue and green light-emitting diodes (LEDs) have been extensively investigated as potential replacements for current polar c-plane LEDs. High-power and low-efficiency-droop blue LEDs have been demonstrated on nonpolar and semipolar planes III-nitride due to the advantages of eliminated or reduced polarization-related electric field and homoepitaxial growth. Semipolar (202¯1) and (202¯1¯) LEDs have contributed to bridging “green gap” (low efficiency in green spectral region) by incorporating high indium compositions, reducing polarization effects, and suppressing defects. Other properties, such as low thermal droop, narrow spectral linewidth, small wavelength shift, and polarized emission, have also been reported for nonpolar and semipolar LEDs. In this paper we review the theoretical background, device performance, material properties, and physical mechanisms for nonpolar and semipolar III-nitride semiconductors and associated blue and green LEDs. The latest progress on topics including efficiency droop, thermal droop, green-gap, and three-dimensional nanostructures is detailed. Future challenges, potential solutions, and applications will also be covered.

中文翻译：

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迈向终极效率：平面和 3D 纳米结构非极性和半极性 InGaN 发光二极管的进展和前景

非极性和半极性 III 族氮化物蓝色和绿色发光二极管 (LED) 已被广泛研究作为当前极性 c 面 LED 的潜在替代品。由于消除或减少了与极化相关的电场和同质外延生长的优势，高功率和低效率下垂的蓝色 LED 已在非极性和半极性 III 族氮化物平面上得到证明。半极性 (202¯1) 和 (202¯1¯) LED 通过引入高铟成分、减少偏振效应和抑制缺陷，有助于弥合“绿色间隙”（绿色光谱区域的低效率）。非极性和半极性 LED 还报告了其他特性，例如低热衰减、窄光谱线宽、小波长偏移和偏振发射。在本文中，我们回顾了理论背景，非极性和半极性 III 族氮化物半导体以及相关的蓝色和绿色 LED 的器件性能、材料特性和物理机制。详细介绍了在效率下降、热下降、绿隙和三维纳米结构等主题上的最新进展。还将涵盖未来的挑战、潜在的解决方案和应用。