Strain-engineered high-responsivity MoTe2 photodetector for silicon photonic integrated circuits
Strain-engineered high-responsivity MoTe2 photodetector for silicon photonic integrated circuits
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DOI：
10.1038/s41566-020-0647-4
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发表时间：
2020-06-22
期刊：
影响因子：
35
通讯作者：
Sorger, V. J.
中科院分区：
文献类型：
--
作者：
Maiti, R.;Patil, C.;Sorger, V. J.
在集成光子学中，由于低损耗传输和该光谱区域的光学增益的可用性，诸如1,550 nm之类的特定波长是首选的。对于基于芯片的光电探测器，二维材料具有科学和技术上的相关性质，如静电可调谐和强烈的光-物质相互作用。然而，由于二维过渡金属二卤化物材料具有较大的光学带隙，目前还没有在通信C波段实现有效的光电探测器。在这里，我们展示了一种基于MoTe2的光电探测器，具有很强的光响应(响应率为0.5A W-1)，通过应变工程使二维材料能够在1550 nm处工作在硅光子学中。非平面化的波导结构显示出0.2 eV的带隙调制，导致在非应变的光非活性介质中有很大的光响应。与依赖无间隙带结构的基于石墨烯的光电探测器不同，这种光电探测器的暗电流减少了约100倍，实现了90PW赫兹(-0.5)的高效噪声等效功率。这种应变工程集成光电探测器为集成光电系统提供了新的机遇。
In integrated photonics, specific wavelengths such as 1,550 nm are preferred due to low-loss transmission and the availability of optical gain in this spectral region. For chip-based photodetectors, two-dimensional materials bear scientifically and technologically relevant properties such as electrostatic tunability and strong light-matter interactions. However, no efficient photodetector in the telecommunication C-band has been realized with two-dimensional transition metal dichalcogenide materials due to their large optical bandgaps. Here we demonstrate a MoTe2-based photodetector featuring a strong photoresponse (responsivity 0.5 A W-1) operating at 1,550 nm in silicon photonics enabled by strain engineering the two-dimensional material. Non-planarized waveguide structures show a bandgap modulation of 0.2 eV, resulting in a large photoresponse in an otherwise photoinactive medium when unstrained. Unlike graphene-based photodetectors that rely on a gapless band structure, this photodetector shows an approximately 100-fold reduction in dark current, enabling an efficient noise-equivalent power of 90 pW Hz(-0.5). Such a strain-engineered integrated photodetector provides new opportunities for integrated optoelectronic systems.