Progress and Insight of Van der Waals Heterostructures Containing Interlayer Transition for Near Infrared Photodetectors

Abstract

Van der Waals (vdWs) heterostructures enable bandgap engineering of different 2D materials to realize the interlayer transition via type‐II band alignment leading to broaden spectrum that is beyond the cut‐off wavelength of individual 2D materials. Interlayer transition has a significant effect on the optoelectronic performance of vdWs heterostructure devices, and strong interlayer transition in 2D vdWs heterojunction is always demandable for sufficient charge transfer and rapid speed response. Herein, a state‐of‐the‐art review is presented on recent progress on interlayer transition in vdWs heterostructures for near‐infrared (NIR) photodetectors. First, the general synthesis techniques for vdWs heterostructures, band alignments in the vdWs heterostructures are provided. Then, the mechanism of interlayer transition in vdWs heterostructure and recent progress on interlayer transition in vdWs heterostructures for NIR photodetectors are summarized. Afterward, some worthy applications of NIR photodetectors are reviewed in related areas of this topic. At the last, an outlook, challenges, and future research directions of vdWs heterostructures for photodetectors at broaden response spectrum are presented.

Self-Powered Photodetector with High Efficiency and Polarization Sensitivity Enabled by WSe2/Ta2NiSe5/WSe2 van der Waals Dual Heterojunction

“…Next, key figures of merit of the DHJ device and SHJ device, such as the light on/off ratio, PCE, EQE, responsivity ( R ), specific detectivity ( D *), and response speed at zero bias under different light power densities are evaluated comprehensively. A lower dark current of ∼200 fA was obtained in the DHJ device (Figure S15a) than that of the SHJ device (∼7 pA), which is ascribed to two strong built-in electrical fields and the bottom mirror electrode underneath the DHJ region in the DHJ device. , The light on/off ratio of the DHJ device, which is calculated by where I light ( I dark ) is the device current under light (dark), increases from 3.59 × 10 3 to 5.5 × 10 5 with the augment of light power density, while a moderate light on/off ratio (2.19 × 10 3 ) is obtained in the SHJ device, as plotted in Figure S16. Besides, the PCE is given by PCE = P el / P in where P in represents effective incident light power density.…”

“…A lower dark current of ∼200 fA was obtained in the DHJ device (Figure S15a) than that of the SHJ device (∼7 pA), which is ascribed to two strong built-in electrical fields and the bottom mirror electrode underneath the DHJ region in the DHJ device. 10,35 The light on/off ratio of the DHJ device, which is calculated by , where I ph , h, c, λ, A, and S n are net photocurrent, Planck constant, the velocity of light, the wavelength of incident light, junction area of the DHJ device and SHJ device, and the noise spectral density, respectively. When it comes to S n , it is well known that the frequency-independent white noise, close to the shot noise floor, dominates the noise behavior without applied bias, 64 and thus, S n in the DHJ device and the SHJ device can be extracted as 1.08 × 10 −15 and 1.15 × 10 −15 A/Hz 1/2 , respectively, through conducting the Fourier transform of dark current trace, as shown in Figure S15b.…”

“…Given the needs of IoT application and low power dissipation, self-powered photodetectors that convert light into electric signals in the absence of external bias have ushered in research and development boom in a variety of fields like thermal imaging, surveillance, optical communication, environmental monitoring, and so forth. − Especially, 2D vdW heterostructures driven by the built-in electric field provide a degree of freedom for self-powered photodetection with on-chip integration technology, which benefit from adjustable atomic thicknesses, negligible lattice mismatching constraints, the strong layer-by-layer coupling effect, etc. − A wealth of all-2D vdW SHJ devices fabricated by the artificial stacking or vdW epitaxy techniques have been reported to realize self-powered photodetection. For example, Xin et al reported an artificial stacked GeSe/MoS 2 vdW heterojunction photodetector with a moderate EQE of 24.2% .…”

Uncovering the photoelectronic/catalytic property modulation and applications of 2D MoS2: from the perspective of constructing heterogeneous interfaces

“…65 In type I HSs, the CBM and VBM are in the same material. 66 Electrons and holes will transfer from the wider band gap material to the narrower one in the form of excitons, to achieve the concentration of electrons and holes in one material. This structure is suitable for applications such as light capture, optical signal amplification, energy harvesting and light-emitting diodes.…”

Recent advances in MXenes: a future of nanotechnologies

“…M n +1 X n T x ( n = 1 to 4) is a common formula for 2D MXene NMs, where M indicates transition metals (TMs) 3,5,6,13,20,49–80 and X indicates carbon or nitrogen, respectively 1,7–10,15,16,18,23,25,35,81–126 . Also, T x (where x varies) denotes single or mixed termination groups (for example, T = S, O, NH, F, Cl, Br, Te, OH, Se), as shown in Fig.…”