Infrared Photodetection from 2D/3D van der Waals Heterostructures

Abstract

An infrared photodetector is a critical component that detects, identifies, and tracks complex targets in a detection system. Infrared photodetectors based on 3D bulk materials are widely applied in national defense, military, communications, and astronomy fields. The complex application environment requires higher performance and multi-dimensional capability. The emergence of 2D materials has brought new possibilities to develop next-generation infrared detectors. However, the inherent thickness limitations and the immature preparation of 2D materials still lead to low quantum efficiency and slow response speeds. This review summarizes 2D/3D hybrid van der Waals heterojunctions for infrared photodetection. First, the physical properties of 2D and 3D materials related to detection capability, including thickness, band gap, absorption band, quantum efficiency, and carrier mobility, are summarized. Then, the primary research progress of 2D/3D infrared detectors is reviewed from performance improvement (broadband, high-responsivity, fast response) and new functional devices (two-color detectors, polarization detectors). Importantly, combining low-doped 3D and flexible 2D materials can effectively improve the responsivity and detection speed due to a significant depletion region width. Furthermore, combining the anisotropic 2D lattice structure and high absorbance of 3D materials provides a new strategy in high-performance polarization detectors. This paper offers prospects for developing 2D/3D high-performance infrared detection technology.

Keywords: 2D materials; 2D/3D infrared detectors; bulk infrared materials; heterojunction; infrared detection.

Figure 1

Physical properties comparison of 2D materials and 3D materials. (a) Bandgap comparison of 2D materials and 3D materials and spectral radiance for different temperature sources [17,54,55,56,57,58,59,60]. (b) Thickness-normalized EQE for different materials: the scatter represents the 2D-layered materials, while the line represents traditional thin film materials [17,45,61,62,63,64,65,66,67,68,69,70,71]. (Hollow symbol represents measured results of laser source, and solid symbol and solid lines represent the result of blackbody source.) (c) Comparison of carrier mobility in different crystal system. Graphene and HgCdTe exhibit ultra-high carrier mobility, orthorhombic BP, PdSe₂ and triclinic ReSe₂, ReS₂ exhibit polarization-sensitive properties [57,72,73,74,75,76,77,78,79,80].

Figure 2

High-quality van der Waals heterojunction interface and modulation of 2D materials P, N conduction type. Schematic diagrams and TEM images of (a) BP/MoS₂/graphene photodetector [45] (copyright 2021, Springer Nature). (b) InSe/BP heterojunction [46] (copyright 2019, Springer Nature). (c) BP/MoS₂/Si two-color infrared detector [48] (copyright 2022, Springer Nature). (d) Schematic diagram of conductive type of PtSSe with controllable layer thickness switching by Ar+ plasma etching [52] (copyright 2021, John Wiley and Sons). (e) Schematic diagram of Ta doping to achieve changing of MoSe₂ conduction type [53] (copyright 2021, John Wiley and Sons).

Figure 3

Advantages and disadvantages of 2D and 3D materials and the superiority of 2D/3D infrared photodetection.

Figure 4

Broadband infrared photodetection. (a) Schematic diagram of p-GaSe/n-GaSb vertical heterostructure detector [83] (copyright 2017, John Wiley and Sons). (b) Wavelength-dependent photoresponsivity of GaSe/GaSb detector [83] (copyright 2017, John Wiley and Sons). (c) Schematic diagram of ultra-broadband Gr/InSb heterostructure photodetector [84] (copyright 2017, AIP Publishing). (d) Current–voltage characterizations of Gr/InSb heterostructure photodetector (473 nm–10 μm) [84] (copyright 2017, AIP Publishing). (e) Schematic diagram of RGO–MoS₂/pyramid Si detector [85] (copyright 2018, John Wiley and Sons). (f) UV–NIR absorption spectra of RGO–MoS₂/pyramid Si detector [85] (copyright 2018, John Wiley and Sons). (g) Schematic diagram of PdSe₂/CdTe heterojunction infrared detector for broadband to 10.6 µm [82] (copyright 2021, American Chemical Society). (h) Photoresponse properties of PdSe₂/CdTe detector [82] (copyright 2021, American Chemical Society).

Figure 5

High-responsivity infrared photodetection. (a,c) Schematic diagrams of photogating effect [90] (copyright 2017, John Wiley and Sons). (b) Schematic diagram of graphene/Si:Ag heterostructure infrared detector and its EQE [92] (copyright 2022, Elsevier). (d) Schematic diagram of energy band structure and responsivity of graphene/Si:B detector [93] (copyright 2022, American Chemical Society). (e) Schematic diagram of graphene/undoped InSb heterostructure infrared detector and its responsivity [94] (copyright 2022, AIP Publishing). (f) Schematic diagram of graphene/insulation/silicon detector and its optical power-dependent responsivity [99] (copyright 2021, Springer Nature).

Figure 6

Fast-response infrared photodetection. (a) Optical microscope image of WSe₂/Ge infrared detector [105] (copyright 2021, John Wiley and Sons). Its rising and falling time under light modulation at (b) 639 nm and (c) 1550 nm [105] (copyright 2021, John Wiley and Sons). (d) Schematic diagram of graphene/HgCdTe(MCT) van der Waals heterojunction photodetector [106] (copyright 2021, John Wiley and Sons). (e) Relative response versus switching frequency [106] (copyright 2021, John Wiley and Sons). (f) Time response of graphene/HgCdTe(MCT) photodetector under 3980 nm pulse laser [106] (copyright 2021, John Wiley and Sons).

Figure 7

Two-color infrared detector. (a) Schematic diagram of p-Ge/n-MoS₂ two-color infrared detector for VIS and infrared selective detection [112] (copyright 2021, American Association for the Advancement of Science). (b,c) Energy band diagrams under infrared light and visible light, respectively [112] (copyright 2021, American Association for the Advancement of Science). (d) Current–voltage curves under 1550 nm infrared light and 406 nm visible light [112] (copyright 2021, American Association for the Advancement of Science). (e) Schematic diagram of BP/MoS₂/Si vdW two-color infrared detector for NWIR and MWIR detection [48] (copyright 2022, Springer Nature). (f) Energy band diagram of BP/MoS₂/Si heterostructure [48] (copyright 2022, Springer Nature). (g) Normalized response of two-color detector at NIR and MWIR [48] (copyright 2022, Springer Nature).

Figure 8

Polarization infrared detector. (a) Schematic diagram of polarization-sensitive HgCdTe/BP detector [118] (copyright 2021, American Association for the Advancement of Science). (b) Photocurrent experiment data with 637 nm laser illumination of HgCdTe/BP detector [118] (copyright 2021, American Association for the Advancement of Science). (c) Schematic diagram of Gr/PdSe₂/Ge heterojunction photodetector with highly polarization-sensitive [119] (copyright 2019, American Chemical Society). (d) Photocurrent of Gr/PdSe₂/Ge detector as a function of polarization angle at zero bias [119] (copyright 2019, American Chemical Society). (e) Schematic diagram of Te/Si heterojunction detector [120] (copyright 2022, Royal Society of Chemistry). (f) Normalized photocurrent with 635 nm laser at zero bias voltage [120] (copyright 2022, Royal Society of Chemistry).