Recent Advances in Broadband Photodetectors from Infrared to Terahertz

Abstract

The growing need for the multiband photodetection of a single scene has promoted the development of both multispectral coupling and broadband detection technologies. Photodetectors operating across the infrared (IR) to terahertz (THz) regions have many applications such as in optical communications, sensing imaging, material identification, and biomedical detection. In this review, we present a comprehensive overview of the latest advances in broadband photodetectors operating in the infrared to terahertz range, highlighting their classification, operating principles, and performance characteristics. We discuss the challenges faced in achieving broadband detection and summarize various strategies employed to extend the spectral response of photodetectors. Lastly, we conclude by outlining future research directions in the field of broadband photodetection, including the utilization of novel materials, artificial microstructure, and integration schemes to overcome current limitations. These innovative methodologies have the potential to achieve high-performance, ultra-broadband photodetectors.

Keywords: broadband photodetectors; infrared; photoelectric detectors; terahertz; thermoelectric detectors.

Figure 6

PTE−type broadband photodetectors based on other materials. (a) Schematic of the EuBiSe₃–metal contact device and the voltage response with spectral variation. Reproduced with permission from ref. [63], Copyright © 2019 American Chemical Society. (b) Schematic of the HfTe₅−metal contact device, R_V and NEP at different wavelengths, and rise times of crystals. Reproduced with permission from ref. [64], Copyright © 2020 WILEY−VCH Verlag GmbH & Co. KGaA, Weinheim. (c) Structure and mechanism schematic of the LSG/CsPbBr₃ PD, and the ultra−broadband R and NEP curves of the device with the wavelength range from UV to THz. Reproduced from ref. [66] under the Creative Common license CC BY. (d) Schematic illustration of MAPbI₃/PEDOT: PSS PD and photocurrent and ΔT of the device under 1064 nm and 2.52 THz laser irradiation at 0.8 mW. Reproduced from ref. [67] under the Creative Common license CC BY−NC.

Figure 7

PCE−type broadband photodetectors. (a) Schematic of the hybrid antenna. Reproduced from ref. [71] under the Creative Common license CC BY. (b) Schematic of a multiband detector, typical field distribution for antenna coupling, and the responsivity and NEP of the detector with respect to temperature. Reproduced from ref. [72] under the Creative Common license CC BY. (c) Structure diagram, band diagram, and detection mechanism of p−GaAs HIWIP detector. Reproduced with permission from ref. [74], Copyright © 2018 AIP Publishing. (d) Structure of HIWIP−LED upconverter device, photocurrent spectrum, and responsivity under different bias voltages of HIWIP−LED at 3.5 K. Reproduced from ref. [75] under the Creative Common license CC BY. (e) Ge:P BIB detector schematic and detector response spectra at different bias voltages. Reproduced from ref. [77] under the Creative Common license CC BY.

Figure 1

Electromagnetic spectrum and the applications of IR/THz photodetectors. Reproduced with permission from ref. [9] under the Creative Common license CC BY−NC−ND.

Figure 2

Schematic illustration of photodetection mechanisms. Reproduced with permission from ref. [1], Copyright © 2018 WILEY−VCH Verlag GmbH & Co. KGaA, Weinheim and [3], Copyright © 2021 Wiley−VCH GmbH.

Figure 3

PBE−type broadband photodetectors. (a) Test schematic diagram and response principle of CA film. Reproduced with permission from ref. [47], Copyright © 2020 Elsevier Ltd. (b) Schematic diagram of logarithmic−periodic antenna. Reproduced with permission from ref. [48], Copyright © 2013 AIP Publishing. (c) Schematic and performance of a fully suspended RGO thin film−photodetector. Reproduced with permission from ref. [49], Copyright © 2017 Elsevier Ltd. (d) Schematic diagram of the millimetric device structure and the light response curve under different laser irradiation in air and vacuum. Reproduced with permission from ref. [50], Copyright © 2018 American Chemical Society. (e) Structural diagram of the VO₂ (B) device, the multiband optical response, and terahertz imaging results. Reproduced with permission from ref. [51], Copyright © 2022 American Chemical Society.

Figure 4

Two-dimensional carbon-based PTE-type broadband photodetectors. (a) Schematic structure, band profiles, and the responsivity of the 3D GF photodetector. Reproduced from ref. [53] under the Creative Common license CC BY. (b) Schematic, photovoltage responsivities, and power dependence of the photovoltage for the rGO photodetector. Reproduced with permission from ref. [55], Copyright © 2019 Elsevier Ltd. (c) Schematic cross-section of the Pd-rGO-Ti photodetector and the photovoltage on–off curve under 2.52 THz illumination. Reproduced from ref. [56] under the Creative Common license CC BY-NC.

Figure 5

CNT and other two−dimensional materials−based PTE−type broadband photodetectors. (a) Schematic of CNT fiber optic photodetector measurement. Reproduced with permission from ref. [57], Copyright © 2018 American Physical Society. (b) Schematic of self−powered CNTF photodetector and detectivity as a function of wavelength. Reproduced with permission from ref. [58], Copyright © 2019 American Physical Society. (c) Schematic diagram of the heterojunction device and the ΔI–V curves of their radiated by lasers with wavelengths. Reproduced from ref. [60] under the Creative Common license CC BY. (d) A 3D schematic of SnSe₂−based photodetector. Reproduced with permission from ref. [61], Copyright © 2020 IOP Publishing, Ltd. (e) Schematic of NbS₃−based detector and the photovoltage responsivities in different wavelengths of the photovoltage at room temperature. Reproduced with permission from ref. [62], Copyright © 2020 American Chemical Society.

Figure 8

PVE−type broadband photodetectors. (a) The structure of a ratchet photodetector, schematic diagram of infrared/terahertz light response, and broadband response achieved by the detector throughout the entire response range. Reproduced with permission from ref. [82], Copyright © 2021 AIP Publishing. (b) Structural diagram of RP−LED upconverter and photocurrent spectrum in the range of 4–20 THz at a specific bias voltage. Reproduced from ref. [83] under the Creative Common license CC BY−NC. (c) Schematic of the RGO SiNW array and photocurrent response in the infrared/terahertz band. Reproduced with permission from ref. [84], Copyright © 2014 WILEY−VCH Verlag GmbH & Co. KGaA, Weinheim. (d) Bi₂Te₃−Si heterojunction photodetector and its energy band schematic under reverse source–drain bias. Reproduced with permission from ref. [85], Copyright © 2015 Royal Society of Chemistry.

Figure 9

Broadband photodetectors based on multiple mechanisms. (a) Schematic structure of the MAPbI₃ photodetector, ultra−broadband photocurrent in the wavelength range from 400 nm to 118 μm, and full−spectrum photoresponsivity of the MAPbI₃ photodetector. Reproduced with permission from ref. [104], Copyright © 2020 American Chemical Society. (b) Schematic of a 3D GFET, simulated distribution of electric field magnitudes in the vicinity of the device, and comparison of the voltage optical response of a 2D GFET and a 3D GFET. Reproduced from ref. [105] under the Creative Common license CC BY−NC. (c) Schematic diagram of an ultra−broadband PMN−PT photodetector and spectral response of the photodetector measured over a wide wavelength range from 375 nm to 118.8 μm. Reproduced with permission from ref. [106], Copyright © 2016 American Chemical Society.

Figure 10

Broadband photodetectors based on the EIW effect. (a) Schematic structure of a Te detector and its detection mechanism in different bands. Reproduced from ref. [107] under the Creative Common license CC BY. (b) Schematic structure of a Bi₂O₂Se terahertz photodetector with symmetric bowtie antenna electrodes, responsivity at 0.17 THz radiation, and imaging of a metal key at THz. Reproduced with permission from ref. [108], Copyright © 2021 Wiley−VCH GmbH. (c) Schematic structure of VSe₂ nanosheet photodetector, R and D* of the device versus incident wavelength, and spectral response of the device at 0.22–0.33 THz frequency at different bias voltages. Reproduced with permission from ref. [109], Copyright © 2020 American Chemical Society. (d) Schematic of a 3D MSM−structured Si detector with broadband detection in the electromagnetic spectrum and an image of a blade inside a plastic foam at 0.269 THz. Reproduced with permission from ref. [110], Copyright © 2022 Royal Society of Chemistry.