Electrostatic Coupling in MoS₂/CuInP₂S₆ Ferroelectric vdW Heterostructures

Abstract

Ferroelectric van der Waals (vdW) heterostructure have recently emerged as a low-power, versatile device paradigm because it combines the great diversity of the 2D materials and the memory nature of ferroelectrics. The non-volatile field effect generated by the polarization bound charge is the pivotal factor for the device's performance. Unfortunately, microscopic studies on the interplay between polarization switching and electrostatic coupling at the heterojunction remain largely overlooked. Herein, the authors investigate the electrostatic coupling phenomena of vdW heterostructures consisting of semiconducting MoS 2 and ferroelectric CuInP 2 S 6 . Significant charge injection accompanying the polarization reversal appears to be the governing field effect that modulates the electronic and photoluminescent properties of MoS 2 , as revealed by correlated ferroelectric domain, surface potential, and photoluminescence microscopies. Conversely, the photoactivity of the MoS 2 also affects the polarization stability of CuInP 2 S 6 . This work provides direct microscopic insight into the mutual electrostatic interactions in vdW ferroelectric-semiconductor heterojunctions, which has broad implications for ferroelectric field-effect applications.

Ferroelectricity-Driven Self-Powered Weak Temperature and Broadband Light Detection in MoS2/CuInP2S6/WSe2 van der Waals Heterojunction Nanoarchitectonics

“…Figure a,b presents the Raman spectrum of MoS 2 , WSe 2 , CIPS, and MoS 2 /CIPS/WSe 2 vdW heterojunction, which can confirm the crystal quality of these regions. The two strong peaks of MoS 2 and WSe 2 nanoflakes are E 2g 1 and A g 1 modes, which belong to in-plane and out-of-plane lattice vibration, respectively. , For the CIPS nanoflakes, there are six active modes for the P 2 S 6 4– , S–P–P, S–P–S, Cu + /In 3+ , P–P, and P–S, all of which are consistent with literature reports. , Figure c displays the EDS spot image of the overlapping area of the three materials; the W, Se, Mo, S, Cu, In, and P elements are evenly spread in the heterojunction, including the substrate Si and O element, which is due to the strong penetration effect of X-ray and its depth can reach 1 μm. The inset in Figure c shows the SEM image and EDS mapping images of the MoS 2 /CIPS/WSe 2 vdW heterojunction, which shows the distribution of W, Se, Mo, S, Cu, In, and P elements and the ordered stacking of the three materials.…”

“…24,25 For the CIPS nanoflakes, there are six active modes for the P 2 S 6 4− , S−P−P, S−P−S, Cu + /In 3+ , P−P, and P−S, all of which are consistent with literature reports. 26,27 Figure 1c displays the EDS spot image of the overlapping area of the three materials; the W, Se, Mo, S, Cu, In, and P elements are evenly spread in the heterojunction, including the substrate Si and O element, which is due to the strong penetration effect of X-ray and its depth can reach 1 μm. The inset in Figure 1c shows the SEM image and EDS mapping images of the MoS 2 / CIPS/WSe 2 vdW heterojunction, which shows the distribution of W, Se, Mo, S, Cu, In, and P elements and the ordered 2d, and the CIPS functional layer is sandwiched between MoS 2 and WSe 2 .…”

A polar-switchable and controllable negative phototransistor for information encryption

“…This observation results indicate that the oscillator spring can be affected by an extra interlayer interaction term, leading to a stiffening of the A 1g vibrational mode. 27 In order to analyze the ferroelectric properties of the CIPS flakes on a Au/SiO 2 /Si substrate, we conducted phase and amplitude hysteresis loops using Dual AC Resonance-Tracking Piezoresponse Force Microscope (DART-PFM) at a single point in tapping mode. 26,[28][29][30] Fig.…”

An all-two-dimensional Fe-FET retinomorphic sensor based on the novel gate dielectric In2Se3−xOx

“…Meanwhile, ferroelectric gates usually show a high dielectric constant, indicating a better potential for modulating channel conductivity. 13 Because conventional 3D ferroelectric materials cannot be reduced to nanometer scale, 13,14 emerging 2D ferroelectric materials (represented by α-In 2 Se 3 ) could be better candidates 15,16 for retinomorphic devices and chips. [17][18][19][20] A shortcoming of 2D ferroelectric dielectric materials is their poor insulation.…”