Ultrafast response of spontaneous photovoltaic effect in 3R-MoS2-based heterostructures

Jingda Wu; Dongyang Yang; Jing Liang; Max Werner; Evgeny Ostroumov; Yunhuan Xiao; Kenji Watanabe; Takashi Taniguchi; Jerry I. Dadap; David Jones; Ziliang Ye

arXiv · 2211.06746

Ultrafast response of spontaneous photovoltaic effect in 3R-MoS2-based heterostructures

Jingda Wu·Dongyang Yang·Jing Liang·Max Werner·Evgeny Ostroumov·Yunhuan Xiao·Kenji Watanabe·Takashi Taniguchi·Jerry I. Dadap·David Jones·Ziliang Ye

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Abstract

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.

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Jingda Wu, Dongyang Yang, Jing Liang, Max Werner, Evgeny Ostroumov, Yunhuan Xiao, Kenji Watanabe, Takashi Taniguchi, Jerry I. Dadap, David Jones, Ziliang Ye. 2022-11-12. Ultrafast response of spontaneous photovoltaic effect in 3R-MoS2-based heterostructures. https://arxiv.org/abs/2211.06746

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