The effects of an intrinsic nonpolar surface on internal quantum efficiency (IQE) are numerically investigated for gallium nitride (GaN)‐based micro‐light emitting‐diodes (μ‐LEDs). It is found that due to the modulation of the surface density of states, the surface energy band bends upward, and valence band holes are naturally pushed toward the surface and are accumulated at the surface, resulting in significant nonradiative recombination. Consequently, the intrinsic surface states remarkably affect the IQE of μ‐LEDs with a size of less than 30 μm due to the large surface‐to‐volume ratio, whereas the IQE of devices with a size of more than 30 μm is relatively insensitive to the intrinsic surface states. IQE starts to decrease for devices with a size of 30 μm, even without considering sidewall damage. In particular, starting from a size of 10 μm, μ‐LEDs suffer a significant efficiency loss and the peak current density shifts to a higher value. The results open the way to improving device performance of μ‐LEDs down to 1 μm and beyond, by incorporating surface band engineering combined with surface passivation over the full range of microdisplay applications.

中文翻译：

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本征表面态在基于GaN的微发光二极管效率衰减中的作用

对于基于氮化镓（GaN）的微发光二极管（μ-LED），通过数值研究了本征非极性表面对内部量子效率（IQE）的影响。发现由于状态的表面密度的调节，表面能带向上弯曲，并且价带孔自然地被推向表面并累积在表面上，从而导致显着的非辐射复合。因此，由于较大的表面体积比，固有表面状态会显着影响尺寸小于30μm的μ-LED的IQE，而尺寸大于30μm的器件的IQE相对不敏感。本征表面状态。即使不考虑侧壁损坏，对于尺寸为30μm的器件，IQE也开始降低。特别是从10μm的尺寸开始，μ-LED会明显损失效率，并且峰值电流密度会移至更高的值。通过在整个微显示器应用范围内采用表面带技术与表面钝化相结合的方法，结果为改善低至1μm甚至更高的μ-LED的器件性能开辟了道路。