Photo‐Detectable Light‐Emitting Devices with Epitaxial Nanowire Photonic Crystals

There is a growing demand for multifunctional optoelectronic systems for various applications such as environmental monitoring, data processing, and information displays. Conventional approaches rely on integrating separate light‐emitting and photo‐detecting components, which leads to an increased system complexity, various fabrication challenges, and large system footprint. Bifunctional optoelectronic devices offer a promising solution by being able to emit and detect light at a single device level. Herein, III‐nitride epitaxial nanowire photonic crystals (epi‐NPCs) for bifunctional optoelectronic devices are investigated. III‐nitride semiconductors, particularly in the form of nanowires, are highly attractive for such devices due to their excellent material quality and electrical doping, as well as the tunable bandgaps from the ultraviolet (UV) to the near‐infrared. Moreover, nanowires in a format of photonic crystals enable precise control over light emission and absorption. Through engineering the photonic bands and material composition, excellent tuning of light emission properties such as the far‐field radiation pattern, spectral linewidth, as well as the light emission wavelength is shown. Notably, surface‐emitting UV lasing is made possible. It is further shown that such devices can be operated in the photodetection mode. As an example, UV photodetection is demonstrated using the UV lasing device.