Emergent Fabry–Pérot Interference for Light–Matter Interaction in van der Waals WS₂/SiP₂ Heterostructures

Abstract

Fabry−Peŕot interference plays an important role in modulating the spectral intensity of optical response originating from light−matter interactions. Examples of such interference occurring in the substrate as the resonating cavity have been demonstrated and probed by two-dimensional layered materials. Similarly, the Fabry−Peŕot interference can occur and modulate the optical response in the heterostructure; however, this remains elusive. Herein, we observe the Fabry−Peŕot interference on photoluminescence (PL) and Raman spectra in monolayer WS 2 / SiP 2 heterostructures by varying the thickness of bottom SiP 2 from 2 to 193 nm, which serves as the Fabry−Peŕot cavity. Both the intensities of the PL spectra and the E 2g1 Raman mode of WS 2 /SiP 2 heterostructures first decrease to almost zero while displaying an interference increase at a SiP 2 thickness of 75 nm. Our findings clearly demonstrate the Fabry−Peŕot interference in the optical response of heterostructures, providing crucial information to optimize the optical response and paving the way toward photodetector applications.

Quasi‐1D ZrS3 as an Anisotropic Nano‐Reflector for Manipulating Light–Matter Interactions

“…[ 39,40 ] The PL intensity of monolayer MoS 2 reduces on the heterostructure region, which might be attributed to the formation of type‐II band alignment shown in Figure 2f, [ 33,37 ] or the FP interference from the underlying ZrS 3 layer. [ 41,42 ]…”

“…Previous explorations have discovered that the intensities of optical reflectivity, Raman modes and PL emissions of a 2D flake can be strongly affected by the bottom stacked layers or multi‐layer structured substrates, where the two parallel reflecting surfaces form a FP cavity and modulate the reflected light. [ 41,42,45,46 ]…”

“…[39,40] The PL intensity of monolayer MoS 2 reduces on the heterostructure region, which might be attributed to the formation of type-II band alignment shown in Figure 2f, [33,37] or the FP interference from the underlying ZrS 3 layer. [41,42] To further investigate the optical modulation of ZrS 3 to the stacked MoS 2 , we applied the angle-resolved polarized Raman and PL spectroscopic characterizations on the heterostructure, which are powerful tools to detect the in-plane optical anisotropy of the structure through light-matter interactions. The optical anisotropy of individual ZrS Raman spectra presented in Figure 1b.…”

“…Previous explorations have discovered that the intensities of optical reflectivity, Raman modes and PL emissions of a 2D flake can be strongly affected by the bottom stacked layers or multi-layer structured substrates, where the two parallel reflecting surfaces form a FP cavity and modulate the reflected light. [41,42,45,46] Therefore, by treating the underlying anisotropic ZrS 3 layer as an FP cavity, the interference effect in MoS 2 will depends on the polarization states of the incident laser. As previously reported, [27,28,35] shown in Figure 1c-g.…”

2D SiP2/h-BN for a Gate-Controlled Phototransistor with Ultrahigh Sensitivity

“…Photodetectors with high sensitivity have attracted a great deal of attention because of their applications in night-time surveillance, astronomical observation, and medical imaging, especially under low light. − Two-dimensional (2D) materials such as graphene, MoS 2 , and black phosphorus (BP) have been widely developed for photodetectors due to their fascinating optoelectronic properties. However, most of them are not competent for ultrasensitive photodetection owing to the high dark currents and low detectivity. , Recently, a new family of group IV and group V 2D layered materials such as GeP, GeAs 2 , SiAs 2 , SiP, and SiP 2 have emerged as promising candidate 2D materials for high-performance photoelectric devices. − As an important member of group IV and group V 2D materials, SiP 2 is a new semiconductor with a tunable bandgap (1.99–2.25 eV), strong light absorption ability, and excellent air stability. − In addition, the high carrier mobility of 1.069 × 10 5 cm 2 V –1 s –1 was theoretically predicted for monolayer SiP 2 , which can be comparable to that of graphene . Notably, the intrinsic anisotropic structure induced by zigzag phosphorus–phosphorus chains in 2D SiP 2 directly results in unique physical properties, revealing an unconventionally bright exciton with hybrid dimensionality of band-edge states .…”