Strain‐Plasmonic Coupled Broadband Photodetector Based on Monolayer MoS₂

Abstract

Abstract2D Semiconductors are promising in the development of next‐generation photodetectors. However, the performances of 2D photodetectors are largely limited by their poor light absorption (due to ultrathin thickness) and small detection range (due to large bandgap). To overcome the limitations, a strain‐plasmonic coupled 2D photodetector is designed by mechanically integrating monolayer MoS2 on top of prefabricated Au nanoparticle arrays. Within this structure, the large biaxial tensile strain can greatly reduce the MoS2 bandgap for broadband photodetection, and at the same time, the nanoparticles can significantly enhance the light intensity around MoS2 with much improved light absorption. Together, the strain‐plasmonic coupled photodetector can broaden the detection range by 60 nm and increase the signal‐to‐noise ratio by 650%, representing the ultimate optimization of detection range and detection intensity at the same time. The strain‐plasmonic coupling effect is further systematically characterized and confirmed by using Raman and photoluminescence spectrophotometry. Furthermore, the existence of built‐in potential and photo‐switching behavior is demonstrated between the strained and unstrained region, constructing a self‐powered homojunction photodetector. This approach provides a simple strategy to couple strain effect and plasmonic effect, which can provide a new strategy for designing high‐performance and broadband 2D optoelectronic devices.

Superior Performances of Self‐Driven Near‐Infrared Photodetectors Based on the SnTe:Si/Si Heterostructure Boosted by Bulk Photovoltaic Effect

“…Moreover, D* is another key parameter that quantitatively evaluates the capability to detect weak light. Assuming that the dark current is dominated by shot noise and at a bandwidth of 1 Hz, [ 20 ] D* is defined as: [ 32,33 ] $$\[ \begin{array}{*{20}{c}}{{D^ * } = \sqrt A \;R/\sqrt {2q{I_{{\rm{dark}}}}} }\end{array} \]$$where A , I dark , R , and q represent the heterostructure area, dark current, responsivity, and unit charge, respectively. Accordingly, D* values were calculated, as shown in Figure 3c,d.…”

Hierarchical Nanoscale Structuring of Solution-Processed 2D van der Waals Networks for Wafer-Scale, Stretchable Electronics

“…33 Based on a previous study that showed wrinkling of monolayer MoS 2 by strain relief of a prestrained elastomer substrate did not increase the carrier mobility, 53 we believe that the strain-induced mobility enhancement effect would not be evident in our system. Because 2D semiconductors typically generate more photoelectrons when light absorption is higher, 22,54,55 we expected that the photoresponsivity of the MoS 2 layer would be higher when the number of wrinkle generations increases. Figures 3g and S6 show the spectral photoresponsivities (R) of the samples at a constant optical power density (P ≈ 10 μW cm −2 , light exposure time: 30 s).…”

“…Because 2D semiconductors typically generate more photoelectrons when light absorption is higher, ,, we expected that the photoresponsivity of the MoS 2 layer would be higher when the number of wrinkle generations increases. Figures g and S6 show the spectral photoresponsivities ( R ) of the samples at a constant optical power density ( P ≈ 10 μW cm –2 , light exposure time: 30 s).…”

Emerging Nonplanar van der Waals Nanoarchitectures from 2D Allotropes for Optoelectronics

“…[12,14,170,180,184] The spectral range of LSPR is closely related to the shape and size of core materials, and the curvature has modulation effect on the band structure of nanoshells. [64,[185][186][187] This provides an important reference for broadband optoelectronics (Figure 9k). [177] The situation of nanoshells is altered when noble metal NP cores are replaced by dielectric materials with high refractive index, such as Si.…”

“…[16,32,60] Second, these novel architectures, different from 2D topology, as a powerful light-matter interaction platform, induce new strong coupling modes (e.g., exciton-polaritons, plasmon-excitons) through WGM mode and Mie resonator, relying on high refractive index medium for multiple scattering and total internal reflection. [14,91,122,187] The mode strength and coupling strength also strongly depend on the size contribution. This is beneficial to function diversification, including advanced plasmonics, construction of room-temperature polaritonic devices, optical switches, and tunable lasers.…”