2D compounds with heterolayered architecture for infrared photodetectors

Abstract

Compounds with heterolayered architecture, as a family of two-dimensional (2D) materials, are composed of alternating positive and negative layers. Their physical properties are determined not only by the charged constituents, but also by the interaction between the two layers. This kind of material has been widely used for superconductivity, thermoelectricity, energy storage, etc. In recent years, heterolayered compounds have been found as an encouraging choice for infrared photodetectors with high sensitivity, fast response, and remarkable reliability. In this review, we summarize the research progress of heterolayered materials for infrared photodetectors. A simple development history of the materials with three-dimensional (3D) or 2D structures, which are suitable for infrared photodetectors, is introduced firstly. Then, we compare the differences between van der Waals layered 2D materials and heterolayered 2D cousins and explain the advantages of heterolayered 2D compounds. Finally, we present our perspective on the future direction of heterolayered 2D materials as an emerging class of materials for infrared photodetectors.

Fig. 1. The diagrams of the mechanisms for (a) the photovoltaic effect, (b) the photoconductive effect, (c) the photothermoelectric effect, and (d) the bolometric effect.

Fig. 2. Timelines of the compounds developed for infrared photodetectors.

Fig. 3. Requirements of the basic properties of materials that could potentially be used for infrared photodetectors.

Fig. 4. (a) Schematic diagram of the broad-band NIR Si Schottky photodetector. (b) Schematic illustration of the B-doped Si-QD/MCT device structure. (c) Structure diagram of the photodetector based on the InGaAs material. (d) Schematic diagram of the graphene-based photodetector. (e) Schematic diagram of the black phosphorus infrared photodetector. (f) Schematic diagram of the MoS₂ infrared photodetector.

Fig. 5. (a) Comparison of the response wavelength ranges of different 2D materials. (b) Diagram of the crystal structures of the well-known 2D compounds.

Fig. 6. (a) Comparison of the crystal structures of typical 2D, heterolayered, and 3D compounds. (b) The reported responsivities of photodetectors of typical 2D, heterolayered, and 3D compounds in the UV to MIR region.

Fig. 7. Scheme of the construction of Bi₂O₂X (X = S, Se, Te).

Fig. 8. (a) Crystal structures of Bi₂O₂S, Bi₂O₂Se and Bi₂O₂Te. (b) Scheme of a bilayer Bi₂O₂Se formed by two monolayers and a zipper model. (c) Bi₂O₂S nanoflower diagram. (d) A single magnified photoresponse curve under infrared light illumination with a light intensity of 30 mW cm⁻². (e) Responsivity and detectivity as a function of the light intensity. (f) The schematic illustration of the photodetector. (g) The responsivities in wavelengths ranging from 405 to 1550 nm. (h) Variation in detectivity as a function of the light intensity at wavelengths ranging from 405 to 1550 nm. (i) Schematic diagram showing the structure of the photodetector, composed of 2D Bi₂O₂Te and the n-Si substrate, with an active area of 4 mm² and responding to a broad wavelength between 210 nm and 2.4 μm. (j and k) Responsivity and detectivity against voltage curves at different wavelengths.

Fig. 9. (a) The schematic illustration of the crystal structure of EuMTe₃ (M = Bi, Sb). (b) RT ab-plane optical absorbance spectrum of EuBiTe₃ crystals. (c) The responsivity for our EuBiTe₃ detectors under illumination with wavelengths from UV to near-infrared (NIR) based on the same device. (d) The schematic diagram of the EuSbTe₃ photodetector. (e) For applied bias 1.2 V, the available ultra-broadband photoresponsivities from UV to THz at various illuminations at 325 nm, 370 nm, 473 nm, 532 nm, 635 nm, 1064 nm, 1550 nm, 10.6 μm, 96.5 μm, 118.8 μm and 163 μm, respectively. (f) The photocurrent as a function of applied bias voltage under 532 nm illumination.

Fig. 10. (a) Ti₃C₂T_x structure diagram. (b) I–V curves under laser irradiation of 1064 nm with different optical power densities. (c) The detectivity and responsivity under different optical power densities at 1064 nm. (d) Structure diagram of Mo₂CT_x. (e) Responsivity of the photodetector as a function of different light intensities. (f) The detectivity of the photodetector as a function of different light intensities.

Fig. 11. (a) The fabrication of the PEC aptamer sensor and the detection mechanism of tumor cells. (b) Ti₃C₂T_x-RAN photodetector monitors laser density display and laser density monitoring system circuit diagram during femtosecond laser surgery.

Fig. 12. (a) MXene/PbS infrared photodetector schematic diagram. (b) A skin-like bilayer photodetector array was prepared on the PI substrate. (c) A schematic diagram of a wireless photodetection system using flexible NFC and NIR-II photodetectors. (d) The schematic diagram of optical communication through NIR-II light.