Patterned tungsten disulfide/graphene heterostructures for efficient multifunctional optoelectronic devices

Abstract

One of the major issues in graphene-based optoelectronics is to scale-up high-performing devices. In this work, we report an original approach for the fabrication of efficient optoelectronic devices from scalable tungsten disulfide (WS)/graphene heterostructures. Our approach allows for the patterned growth of WS on graphene and facilitates the realization of ohmic contacts. Photodetectors fabricated with WS on epitaxial graphene on silicon carbide (SiC) present, when illuminated with red light, a maximum responsivity R ∼220 A W, a detectivity D* ∼2.0 × 10 Jones and a -3 dB bandwidth of 250 Hz. The retrieved detectivity is 3 orders of magnitude higher than that obtained with graphene-only devices at the same wavelength. For shorter illumination wavelengths we observe a persistent photocurrent with a nearly complete charge retention, which originates from deep trap levels in the SiC substrate. This work ultimately demonstrates that WS/graphene optoelectronic devices with promising performances can be obtained in a scalable manner. Furthermore, by combining wavelength-selective memory, enhanced responsivity and fast detection, this system is of interest for the implementation of 2d-based data storage devices.

Superlubricity of epitaxial monolayer WS2 on graphene

“…In particular, tungsten disulfide (WS 2 ) TMD exhibits large carrier mobility [3], high photoluminescence emission [4], significantly large spin-orbit splitting (~ 460 meV) [5], as well as long exciton life and coherence times [6]. Novel field-effect vertical tunneling transistors [7] and photodetectors [8,9] based on WS 2 /graphene stacks have been demonstrated. Although the optoelectronic potential of this 2D heterostack is being extensively studied, relatively little attention has been paid to its nanotribological properties.…”

Synthesis and characterization of WS2/graphene/SiC van der Waals heterostructures via WO3−x thin film sulfurization

“…In this case, in order to produce WS 2 layers a growth temperature of 1100 °C was required (see Figure S6, Supporting Information). Typically WS 2 synthesis by CVD is more challenging than MoS 2 synthesis due to the difficulty in volatilizing the WO 3 precursor, which requires temperatures of exceeding 900 °C 13,28,55,56 . In comparison to WS 2 grown by thin film sulfurization which results in numerous grains of thin (1-3 layers) WS 2 , conventional CVD resulted in the formation of isolated, thick multilayer (> 10 layers) WS 2 crystals.…”

“…In addition, spin polarization in TMDs is complemented by long spin lifetimes in graphene 9 , 10 . When combined in a heterostructure these two materials can deliver outstanding performance in a range of applications including optoelectronics 11 – 13 , spintronics and valleytronics 14 – 16 , sensing 17 , 18 , and energy storage 19 , 20 .…”

Effect of Chemical Vapor Deposition WS2 on Viability and Differentiation of SH-SY5Y Cells

“…Moreover WS 2 has been applied in photothermal and photodynamic therapy, thanks to its good water solubility and high near infrared absorption capability (Chimene et al, 2015). Thanks to its known photoelectric characteristics (Rossi et al, 2018;Wang et al, 2019), WS 2 could be used to realize a stimulating electrode based on the local photocurrent controlled by light, similarly to the light-directed electrical stimulation reported in the past for silicon wafer (Starovoytov et al, 2005). Due to this increasing interest, WS 2 biocompatibility and toxicity tests need to be performed.…”