Integrated Freestanding Two‐dimensional Transition Metal Dichalcogenides

Abstract

This paper reports on the integration of freestanding transition metal dichalcogenides (TMDs). Monolayer (1-L) MoS , WS , and WSe as representative TMDs are transferred on ZnO nanorods (NRs), used here as nanostructured substrates. The photoluminescence (PL) spectra of 1-L TMDs on NRs show a giant PL intensity enhancement, compared with those of 1-L TMDs on SiO . The strong increases in Raman and PL intensities, along with the characteristic peak shifts, confirm the absence of stress in the TMDs on NRs. In depth analysis of the PL emission also reveals that the ratio between the exciton and trion peak intensity is almost not modified after transfer. The latter shows that the effect of charge transfer between the 1-L TMDs and ZnO NRs is here negligible. Furthermore, confocal PL and Raman spectroscopy reveal a fairly consistent distribution of PL and Raman intensities. These observations are in agreement with a very limited points contact between the support and the 1-L TMDs. The entire process reported here is scalable and may pave the way for the development of very efficient ultrathin optoelectronics.

From MoO2@MoS2 Core–Shell Nanorods to MoS2 Nanobelts

“…To highlight the detailed features, the PL intensity has been enlarged by 3 (for MoO 2 @MoS 2 nanorod) and 64 times (for transferred MoS 2 nanobelt). PL intensities of TMDs are affected by many reasons such as the number of layers, doping, and strain . Monolayer MoS 2 has a much stronger PL intensity (about 10 2 times) than bilayer due to the quantum confinement effects .…”

Ultrahigh‐Sensitive Broadband Photodetectors Based on Dielectric Shielded MoTe2/Graphene/SnS2 p–g–n Junctions

“…Photodetectors capable of detecting light in a wide spectrum is central to diversified optoelectronic applications in spectroscopy, remote sensing, imaging and optical communication . Two‐dimensional (2D) transition metal dichalcogenides (TMDs) provide a tremendous potential for broadband optoelectronics due to their relatively high mobility, appropriate bandgaps, and flexibility . In particular, TMD layers of different bandgaps and doping (p or n types) can be stacked together into van der Waals (vdW) heterostructures to enable broadband optoelectronics, which has been a major hurdle in epitaxy of conventional semiconductors of different bandgaps .…”

MoS2 and Perylene Derivative Based Type‐II Heterostructure: Bandgap Engineering and Giant Photoluminescence Enhancement

“…As a result, PL behavior of MoS 2 can be significantly tailored. [6,21,22] To our knowledge, the enhanced PL emission of TMDs could be achieved with the combination of organic semiconductors, such as pentacene, [3] perylene tetracarboxylic dianhydride, [23] titanyl phthalocyanine, [24] and inorganic materials such as lead iodide, [4] ZnO nanorods, [25] 2D layer (BN, MoTe 2 ), [26,27] and metal nanoparticles, [28,29] via charge carrier/energy transfer, strain relaxation, and surface plasmon effects. [3,4,20] In contrast, for TMD hybrid heterostructures with a type-II (staggered) band alignment photoinduced carriers can transfer through the interface and be separated at different material due to the large band offsets.…”