Large area growth of vertically aligned luminescent MoS₂nanosheets

Abstract

Vertically aligned MoS nanosheets (NSs) with exposed edges were successfully synthesized over a large area (∼2 cm). The NSs were grown using an ambient pressure chemical vapor deposition technique via rapid sulfurization of sputter deposited thick molybdenum films. Extensive characterization of the grown MoS NSs has been carried out using high resolution scanning and transmission electron microscopy (SEM & TEM). A special care was given to the TEM lamella preparation process by means of a focused ion beam to preserve the NS growth direction. The cross-section TEM measurements revealed the growth of densely packed, vertically aligned and straight MoS NSs. Additional characterization techniques such as atomic force microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and photoluminescence (PL) were used to evaluate the MoS NSs. These studies revealed the high crystallinity and quality of the synthesized NSs. The MoS NSs show visible light emission similar to mechanically exfoliated monolayer MoS NSs. The striking PL signal comes from the exposed edges as shown by experimental and theoretical calculations. The vertical MoS NSs also exhibit a hydrophobic character with a contact angle of 114°. The as-grown MoS NSs would be highly useful in the development of catalysis, nano-optoelectronics, gas-sensing and bio-sensing device applications.

Noble metal-coated MoS2 nanofilms with vertically-aligned 2D layers for visible light-driven photocatalytic degradation of emerging water contaminants

“…The projected atomic structure of MoS 2 is superimposed on the image, indicating an interlayer spacing of ~0.62 nm. The presented structural model matches the image of the projected MoS 2 atomic structure, indicating that the MoS 2 film predominantly expose the semiconducting 2H hexagonal phases 27 , 28 . For the purpose of photocatalytic performance tests, some MoS 2 films with vertically-aligned 2D layers were coated with thin layers of noble metals.…”

“…2(a) and (b) . We observe that MoS 2 films with a thickness of <10 nm exhibit two emission peaks centered around 1.81 eV and 1.96 eV, corresponding to the A and B excitons of MoS 2 27 . The observation of such strong PL peaks is interesting as they are typically observed in mono-to-few layer horizontal 2D MoS 2 flakes of much smaller thickness (<a few nm) 27 .…”

Nonvolatile Resistive Switching in Nanocrystalline Molybdenum Disulfide with Ion‐Based Plasticity

“…Raman spectroscopy studies conducted on the as‐grown MoS 2 films confirm a 2H‐MoS 2 phase formation. Figure a shows the acquired Raman spectrum with the two prominent peaks corresponding to the and A 1g modes of the 2H‐MoS 2 phase 38. The peak intensity of the A 1g mode is nearly four times higher than that of , indicating the formation of vertically aligned MoS 2 layers 39,40.…”

Effect of rapid thermal annealing on crystallization and stress relaxation of SiGe nanoparticles deposited by ICP PECVD

“…The interdiffusion can be because of high strains and concentration gradient. 26,31 The effect of RTA, for instance is clearly observed on the evolution of strain as a function of annealing time and temperature. For increasing annealing temperature and dwell time, signicant strain relaxation was attained in the Si-Ge layer.…”

“…A standard in situ li out method was implemented for the purpose. [24][25][26] Fig. 1 shows the nature and the aspect of the as-deposited sample.…”