Zero-bias mid-infrared graphene photodetectors with bulk photoresponse and calibration-free polarization detection

Jingxuan Wei,Kah-Wee Ang,Wugang Liao,Cheng Xu,Bowei Dong,Ying Li,Lin Wang,Chengkuo Lee,Chunxiang Zhu,Cheng-Wei Qiu

doi:10.1038/s41467-020-20115-1

Jingxuan Wei, Kah-Wee Ang + Show 8 more

Open Access

https://doi.org/10.1038/s41467-020-20115-1

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Abstract

Bulk photovoltaic effect (BPVE), featuring polarization-dependent uniform photoresponse at zero external bias, holds potential for exceeding the Shockley-Queisser limit in the efficiency of existing opto-electronic devices. However, the implementation of BPVE has been limited to the naturally existing materials with broken inversion symmetry, such as ferroelectrics, which suffer low efficiencies. Here, we propose metasurface-mediated graphene photodetectors with cascaded polarization-sensitive photoresponse under uniform illumination, mimicking an artificial BPVE. With the assistance of non-centrosymmetric metallic nanoantennas, the hot photocarriers in graphene gain a momentum upon their excitation and form a shift current which is nonlocal and directional. Thereafter, we demonstrate zero-bias uncooled mid-infrared photodetectors with three orders higher responsivity than conventional BPVE and a noise equivalent power of 0.12 nW Hz−1/2. Besides, we observe a vectorial photoresponse which allows us to detect the polarization angle of incident light with a single device. Our strategy opens up alternative possibilities for scalable, low-cost, multifunctional infrared photodetectors.

Highlights

Bulk photovoltaic effect (BPVE), featuring polarization-dependent uniform photoresponse at zero external bias, holds potential for exceeding the Shockley-Queisser limit in the efficiency of existing opto-electronic devices
The available materials for the BPVE are primarily limited in ferroelectrics and the emerging topological materials, which suffer from low efficiencies and fabrication difficulties[1,3,12,13]
Under uniform illumination and at zero external bias (Vd = Vg = 0 V), the generated photocarriers are shifted in real space with the direction and magnitude of the shift currents controlled by the polarization of light

Summary

Introduction

Bulk photovoltaic effect (BPVE), featuring polarization-dependent uniform photoresponse at zero external bias, holds potential for exceeding the Shockley-Queisser limit in the efficiency of existing opto-electronic devices. Efficient infrared detection is highly desired with widespread applications such as solar energy harvesting, free-space communication, environmental monitoring, and thermal imaging[15,16,17,18,19,20] It would be of great interest if the BPVE can offer possibilities for uncooled infrared photodetectors with high efficiency and low cost, which remains as one of the major challenges for the current infrared technologies[1,16]. Since the bulk response in our devices originates from the non-centrosymmetric sub-wavelength structure of plasmonic nanoantennas rather than materials, we refer to this effect as an artificial BPVE. We observe vectorial photocurrents in the artificial BPVE, which can be used for unambiguous detection of polarization angles with a single device regardless of the incident power

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