III–nitride light-emitting diodes (LEDs) are the backbone of ubiquitous lighting and display applications. Imparting directional emission is an essential requirement for many LED implementations. Although optical packaging¹, nanopatterning^2,3 and surface roughening⁴ techniques can enhance LED extraction, directing the emitted light requires bulky optical components. Optical metasurfaces provide precise control over transmitted and reflected waveforms, suggesting a new route for directing light emission. However, it is difficult to adapt metasurface concepts for incoherent light emission, due to the lack of a phase-locking incident wave. Here, we demonstrate a metasurface-based design of InGaN/GaN quantum-well structures that generate narrow, unidirectional transmission and emission lobes at arbitrary engineered angles. We further demonstrate 7-fold and 100-fold enhancements of total and air-coupled external quantum efficiencies, respectively. The results present a new strategy for exploiting metasurface functionality in light-emitting devices.

Ⅲ族氮化物发光二极管（LED）是无处不在的照明和显示应用的中坚力量。定向发射是许多LED实施的基本要求。尽管是光学包装¹，但纳米图案化^2,3和表面粗糙化⁴技术可以增强LED的提取效率，引导发射的光需要庞大的光学组件。光学超表面提供了对透射和反射波形的精确控制，为引导光发射提供了一条新途径。然而，由于缺乏锁相入射波，难以使超表面概念适应于非相干光发射。在这里，我们演示了基于InGaN / GaN量子阱结构的基于超表面的设计，该结构可以在任意工程角度下生成狭窄的单向传输和发射波瓣。我们进一步证明总和空气耦合的外部量子效率分别提高了7倍和100倍。结果提供了一种开发发光器件超表面功能的新策略。