Growth of Large-Scale and Thickness-Modulated MoS₂ Nanosheets

Abstract

Two-dimensional MoS2 is a promising material for next-generation electronic and optoelectronic devices due to its unique electrical and optical properties including the band gap modulation with film thickness. Although MoS2 has shown excellent properties, wafer-scale production with layer control from single to few layers has yet to be demonstrated. The present study explored the large-scale and thickness-modulated growth of atomically thin MoS2 on Si/SiO2 substrates using a two-step sputtering-CVD method. Our process exhibited wafer-scale fabrication and successful thickness modulation of MoS2 layers from monolayer (0.72 nm) to multilayer (12.69 nm) with high uniformity. Electrical measurements on MoS2 field effect transistors (FETs) revealed a p-type semiconductor behavior with much higher field effect mobility and current on/off ratio as compared to previously reported CVD grown MoS2-FETs and amorphous silicon (a-Si) thin film transistors. Our results show that sputter-CVD is a viable method to synthesize large-area, high-quality, and layer-controlled MoS2 that can be adapted in conventional Si-based microfabrication technology and future flexible, high-temperature, and radiation hard electronics/optoelectronics.

Atomic rearrangement of a sputtered MoS2 film from amorphous to a 2D layered structure by electron beam irradiation

“…The FWHM of the EBI sample was higher than that of the exfoliated monolayer MoS 2 (FWHM of E 1 2g : 2.8 cm −1 , FWHM of A 1g : 4.7 cm −1 ) 30 . However, the crystallinity of our 1 min EBI-treated sample at room temperature was superior to that of sputtered MoS 2 films (FWHM of E 1 2g : ~50 cm −1 , FWHM of A 1g : ~14 cm −1 ) with a substrate temperature of 300 °C 20 and comparable to that of 5.4 nm thick MoS 2 films (FWHM of E 1 2g : ~12 cm −1 , FWHM of A 1g : ~14 cm −1 ) grown at 600 °C with a hybrid process of sputtering combined with the CVD method 16 . Especially, instead of the long tail for the E 1 2g peak that is commonly observed in the Raman spectra of a MoS 2 film from the sputtering process 20–22 , a relatively short tail was observed in our results.…”

“…In PVD methods, similar problems related with scaling up and the operating temperature still exist. A hybrid sputtering process combined with CVD, which first deposits a Mo film and then progresses to sulfurization via a chemical reaction with sulphur vapour, has recently been reported, but it need sufficient heating of the substrate to over 600 16 or 800 °C 17 . There have been attempts to carry out deposition and sulfurization simultaneously by using a Mo target in hydrogen sulphide (H 2 S) gas 18 and vaporised sulphur ambient 19 .…”

Fabrication of TiO2/MoS2@zeolite photocatalyst and its photocatalytic activity for degradation of methyl orange under visible light

“…However, the conduction band energy level of bulk MoS 2 is less negative than that of TiO 2 . Fortunately, nanoscale MoS 2 exhibited quantum confinement effects as some research reported [16][17][18][19]. Owing to the confinement effects, the band gap of nanoscale MoS 2 can be increased significantly and the energy level of conduction band is higher than that of TiO 2 .…”

A cathodic luminol-based electrochemiluminescence biosensor for detecting cholesterol using 3D-MoS2–PANI nanoflowers and Ag nanocubes for signal enhancement

“…29,30 Compared with the Raman spectra of PANI, the 3D-MoS 2 -PANI nanoflowers exhibited two other Raman characteristic bands at 405 and 379 30 cm -1 (Fig.2 curve b), corresponding to the A 1g and E 1 2g modes of MoS 2 nanostructure, respectively. 31,32 Above results indicated the successful synthesis of 3D-MoS 2 -PANI nanoflowers. …”