Waveguide-integrated van der Waals heterostructure photodetector at telecom wavelengths with high speed and high responsivity
Waveguide-integrated van der Waals heterostructure photodetector at telecom wavelengths with high speed and high responsivity
复制标题
波导集成范德瓦尔斯异质结构光电探测器在电信波长下具有高速度和高响应度
DOI：
10.1038/s41565-019-0602-z
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发表时间：
2020-02-03
影响因子：
38.3
通讯作者：
Novotny, Lukas
中科院分区：
文献类型：
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作者：
Flory, Nikolaus;Ma, Ping;Novotny, Lukas
二维过渡金属二硫属化物（transition-metaldichalcogenides，TMDCs）由于其强的光-物质相互作用和独特的材料特性，引起了人们对新型光电子器件的广泛关注。特别是，具有高速和高响应性能的光电探测器对于大量的应用，例如在标准化电信波长下操作的高数据速率互连，具有极大的兴趣。然而，TMDC固有的小载流子迁移率成为高速应用的瓶颈。在这里，我们提出了高性能的垂直货车德瓦耳斯异质结为基础的光电探测器集成在硅光子平台。我们的垂直MoTe 2-石墨烯异质结构设计最大限度地减少了TMDC中的载流子传输路径长度，并在-3 V的中等偏置电压下实现了至少24 GHz的创纪录测量带宽。应用更高的偏置或采用更薄的MoTe 2薄片将带宽甚至提高到50 GHz。同时，得益于集成波导设计，我们的器件对1,300 nm入射光的外部响应度高达0.2 A W-1。我们的研究揭示了性能的权衡和快速，高效的设备目前的设计准则。二维异质结和集成导波纳米光子学的结合为实现高性能光电器件（如光电探测器、发光器件和电光调制器）提供了一个有吸引力的平台，但TMDC的低载流子迁移率对高速光电探测的应用提出了挑战。将垂直二维异质结构与光子波导集成，可以克服固有的速度限制，并实现创纪录的高光电探测带宽。
Intensive efforts have been devoted to the exploration of new optoelectronic devices based on two-dimensional transition-metal dichalcogenides (TMDCs) owing to their strong light-matter interaction and distinctive material properties. In particular, photodetectors featuring both high-speed and high-responsivity performance are of great interest for a vast number of applications such as high-data-rate interconnects operated at standardized telecom wavelengths. Yet, the intrinsically small carrier mobilities of TMDCs become a bottleneck for high-speed application use. Here, we present high-performance vertical van der Waals heterostructure-based photodetectors integrated on a silicon photonics platform. Our vertical MoTe2-graphene heterostructure design minimizes the carrier transit path length in TMDCs and enables a record-high measured bandwidth of at least 24 GHz under a moderate bias voltage of -3 V. Applying a higher bias or employing thinner MoTe2 flakes boosts the bandwidth even to 50 GHz. Simultaneously, our device reaches a high external responsivity of 0.2 A W-1 for incident light at 1,300 nm, benefiting from the integrated waveguide design. Our studies shed light on performance trade-offs and present design guidelines for fast and efficient devices. The combination of two-diemensional heterostructures and integrated guided-wave nano photonics defines an attractive platform to realize high-performance optoelectronic devices, such as photodetectors, light-emitting devices and electro-optic modulators.The low carrier mobilities of TMDCs pose a challenge for applications in high-speed photodetection. Integrating vertical two-dimensional heterostructures with photonic waveguides allows the intrinsic speed limitations to be overcome and record-high photodetection bandwidths to be achieved.