One of the current challenges in photonics is developing high-speed, power-efficient, chip-integrated optical communications devices to address the interconnects bottleneck in high-speed computing systems¹. Silicon photonics has emerged as a leading architecture, in part because of the promise that many components, such as waveguides, couplers, interferometers and modulators², could be directly integrated on silicon-based processors. However, light sources and photodetectors present ongoing challenges^3,4. Common approaches for light sources include one or few off-chip or wafer-bonded lasers based on III–V materials, but recent system architecture studies show advantages for the use of many directly modulated light sources positioned at the transmitter location⁵. The most advanced photodetectors in the silicon photonic process are based on germanium, but this requires additional germanium growth, which increases the system cost⁶. The emerging two-dimensional transition-metal dichalcogenides (TMDs) offer a path for optical interconnect components that can be integrated with silicon photonics and complementary metal-oxide-semiconductors (CMOS) processing by back-end-of-the-line steps^7,8,9. Here, we demonstrate a silicon waveguide-integrated light source and photodetector based on a p–n junction of bilayer MoTe₂, a TMD semiconductor with an infrared bandgap¹⁰. This state-of-the-art fabrication technology provides new opportunities for integrated optoelectronic systems.

光子学中的当前挑战之一是开发高速，高能效，芯片集成的光通信设备，以解决高速计算系统^1中的互连瓶颈。硅光子学已经成为一种领先的体系结构，部分是因为人们希望将许多组件（例如波导，耦合器，干涉仪和调制器^2）直接集成在基于硅的处理器上。但是，光源和光电探测器仍面临挑战^3,4。常见的光源处理方法包括一个或几个基于III–V材料的片外或与晶圆结合的激光器，但是最近的系统架构研究显示，使用位于发射器位置⁵的许多直接调制光源具有优势。硅光子工艺中最先进的光电探测器基于锗，但这需要额外的锗生长，这会增加系统成本⁶。新兴的二维过渡金属二硫化碳（TMD）为光学互连组件提供了一条途径，该组件可以通过后端步骤⁷与硅光子学和互补金属氧化物半导体（CMOS）处理集成在一起^{， 8,9}。在这里，我们演示了基于双层MoTe ₂（具有红外带隙¹⁰的TMD半导体）的ap-n结的硅波导集成光源和光电探测器。这种最先进的制造技术为集成光电系统提供了新的机会。