The characteristics of monolithically integrated light-emitting diodes (LEDs), photodetectors (PDs), and waveguides on a GaN-on-Si wafer are investigated. The InGaN/GaN multi-quantum wells, which are responsible for blue light emission in LEDs, are also used for photodetection in PDs. Despite the Stokes shift, a spectral overlap of $\sim 25\mathrm{nm}$ between the emission and absorption spectra provides the PDs with sufficient photosensitivity to signals from the emitter while remaining insensitive to ambient lighting. Optical interconnects in the form of linear or bent suspended waveguides bridging the LEDs and PDs are formed by selective detachment of etched GaN mesas from the Si substrate. Additionally, the PDs can be detached from the substrate and remounted on an elevated platform, owing to the flexibility of the thin-film waveguide. The $150\mathrm{\mu m}\times 150\mathrm{\mu m}$ LEDs and PDs exhibit rapid response on nanosecond time scales, which is attributed to fast radiative recombinations as well as minimized resistive-capacitive (RC) delays, enabling transmission of pseudorandom binary sequence (PRBS) data signals at rates of 250 Mb/s with an opening in the eye diagram. Together with multichannel transmission free of crosstalk, the ability of the planar and three-dimensional monolithic photonic systems to handle visible-light communication (VLC) applications is demonstrated.

中文翻译：

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硅衬底上的单片集成InGaN / GaN发光二极管，光电探测器和波导

研究了GaN-on-Si晶片上的单片集成发光二极管（LED），光电探测器（PD）和波导的特性。负责LED中蓝光发射的InGaN / GaN多量子阱也用于PD中的光电检测。尽管有斯托克斯位移，但光谱重叠$〜25\mathrm{纳米}$发射光谱和吸收光谱之间的距离为PD提供了对来自发射器的信号的足够的光敏性，同时保持对环境光不敏感。通过将蚀刻的GaN台面从Si基板上选择性分离，形成桥接LED和PD的线性或弯曲悬浮波导形式的光学互连。此外，由于薄膜波导的灵活性，PD可以从基板上拆下并重新安装在高架平台上。这$150\mathrm{微米}\times 150\mathrm{微米}$LED和PD表现出纳秒级的快速响应，这归因于快速的辐射重组以及最小的阻容（RC）延迟，从而能够以250 Mb / s的速率传输伪随机二进制序列（PRBS）数据信号，并且在眼图中打开。与无串扰的多通道传输一起，展示了平面和三维单片光子系统处理可见光通信（VLC）应用的能力。