We demonstrate the detection of cyclotron resonance in graphene by using a photo-induced thermionic emission mechanism at the graphene/MoS2 van der Waals (vdW) Schottky junction. At cyclotron resonance in Landau-quantized graphene, the infrared light is absorbed and an electron-hole pair is generated. When the energy of a photoexcited electron exceeds the band offset energy at the graphene/MoS2 interface, the electron transfer occurs from graphene to the conduction band of MoS2, and the hole remains in graphene. This creates an electron-hole separation at the graphene/MoS2 interface at cyclotron resonance and a photovoltage is generated. The proposed method is an infrared photodetection technique through out-of-plane transport at the vdW junction, which is distinct from the previously reported methods that use in-plane transport in graphene for electronic detection of the cyclotron resonance. Despite the simple structure of our device with a single-vdW junction, our method exhibits a very high sensitivity of about 10^6 V/W, which shows an improvement of three orders of magnitude over the previously reported values. Therefore, the proposed method displays a high potential for cyclotron resonance-based infrared photodetector applications.
@article{arxiv.1909.08272,
title = {Detection of cyclotron resonance using photo-induced thermionic emission at graphene/MoS2 van der Waals interface},
author = {Yusai Wakafuji and Rai Moriya and Sabin Park and Kei Kinoshita and Satoru Masubuchi and Kenji Watanabe and Takashi Taniguchi and Tomoki Machida},
journal= {arXiv preprint arXiv:1909.08272},
year = {2019}
}
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This article has been published in Applied Physics Letters