论文标题
基于3R-MOS2的异质结构中自发光伏效应的超快响应
Ultrafast response of spontaneous photovoltaic effect in 3R-MoS2-based heterostructures
论文作者
论文摘要
菱形堆积的MOS2已显示出自发极化至双层极限，当将石墨烯夹在石墨烯之间时，可以维持强烈的去极化场。这样的磁场会产生自发的光伏效应，而无需任何P-N结。在这项工作中，我们显示光伏效应的外部量子效率为10 \％，对于仅在低温下具有两个原子层MOS2的设备，并识别出picsecond-fast-fast的光电响应，这将转化为〜100-GHz水平的内在设备带宽。为此，我们开发了一种非分化泵探针光电流光谱技术来反应热和电荷转移过程，从而成功地揭示了光电流动力学的多组分性质。快速组件接近石墨烯-MOS2接口处的电荷转移速度的极限。石墨烯-3R-MOS2设备中的显着效率和超快光响应支持使用铁电范德华材料用于未来的高性能光电应用。
Rhombohedrally stacked MoS2 has been shown to exhibit spontaneous polarization down to the bilayer limit and can sustain a strong depolarization field when sandwiched between graphene. Such a field gives rise to a spontaneous photovoltaic effect without needing any p-n junction. In this work, we show the photovoltaic effect has an external quantum efficiency of 10\% for devices with only two atomic layers of MoS2 at low temperatures, and identify a picosecond-fast photocurrent response, which translates to an intrinsic device bandwidth at ~ 100-GHz level. To this end, we have developed a non-degenerate pump-probe photocurrent spectroscopy technique to deconvolute the thermal and charge-transfer processes, thus successfully revealing the multi-component nature of the photocurrent dynamics. The fast component approaches the limit of the charge-transfer speed at the graphene-MoS2 interface. The remarkable efficiency and ultrafast photoresponse in the graphene-3R-MoS2 devices support the use of ferroelectric van der Waals materials for future high-performance optoelectronic applications.
