针对微显示对高外量子效率、低工作电流和稳定光谱波长的红光LED的需求,提出了一种将共振腔发光二极管与AlAs侧向氧化技术相结合的Micro-RCLED。该器件利用共振腔改变有源区自发辐射场的空间分布,将更多的光分布在光提取角之内以提高光提取效率,而且共振腔还有利于输出光谱波长的稳定。AlAs氧化孔对电流的横向限制既有利于降低侧壁的Shockley-Read-Hall非辐射复合,又可减少漏电,从而提高辐射复合效率。另外,P电极出光孔的直径大于AlAs氧化电流注入孔的直径,因此,金属P电极对出射光的吸收可以有效避免。同时,制作了3个并联的655 nm Micro-RCLED,每个单元的出光孔径为17 μm。 IdV/dI-I曲线的拟合结果表明,120 Ω的串联电阻器件在1 mA时的输出光功率为0.21 mW,外部量子效率大于10%,并且可以在低于1 μA的注入电流下点亮单个单元。另外,当工作电流密度变化12.5倍时,峰值波长仅增加1.5 nm,光谱的半峰全宽仅增加0.33 nm。这使得RCLED作为单色光源在Micro-LED中的应用成为可能。

In response to the needs of micro-displays for red LEDs with high external quantum efficiency, low operating current, and stable spectral wavelength,a Micro-RCLED that combines resonant cavity light-emitting diodes with AlAs lateral oxidation technology is realized. The device changes the spatial distribution of the spontaneous radiation field in the active region by a resonant cavity to concentrate more light within the light extraction angle to improve the light extraction efficiency, meanwhile, the resonant cavity is also beneficial to deminish the shift of the optical spectrum. The lateral current confinement to the AlAs oxide aperture can not only decreasing the Shockley-Read-Hall non-radiative recombination due to the sidewalls defects, but also reducing the leakage current so to improve the radiative recombination efficiency. In addition, the diameter of the light exit aperture of the P electrode is larger than that of the AlAs oxidation aperture, so that the absorption of the outgoing light by the P electrode can be effectively avoided. The 655 nm Micro-RCLED with 3 units parallel connected is fabricated, in which each unit has an exit aperture of 17 μm diameter. Fitting result of IdV/dI-I shows a reasonable 120 Ω series resistance. The output optical power of the device at 1 mA is 0.21 mW, the external quantum efficiency is greater than 10%, and a single unit can be lighted up at an injection current lower than 1 μA. In addition, when the working current density changes by 12.5 times, the peak wavelength only increases by 1.5 nm, and the full width at half maximum of the spectrum increases just 0.33 nm.