Nanoporous Silicon-Assisted Patterning of Monolayer MoS₂ with Thermally Controlled Porosity: A Scalable Method for Diverse Applications

Abstract

Nanoscale pore formation on chemical vapor deposition grown monolayerMoS 2 is achieved using oxygen plasma etching through a nanoporous silicon mask, creating round pores of ~70 nm in diameter. The microscale areas with high porosity were successfully patterned via the usage of silicon masks. Thermal annealing in air after the pore formation in the monolayers results in the gradual enlargement of the pores, providing an effective method of controlling edge-to-area ratio of MoS 2 crystals. The photoluminescence of the Page 1 of 34 ACS Paragon Plus Environment ACS Applied Nano Materials 2 nanoporous MoS 2 exhibits rapid increase and blue-shift due to facile p-doping during the thermal annealing process, compared to pristine MoS 2 . This method of fabricating porous transition metal dichalcogenide layers with controlled edge densities presents opportunities in various applications that require atomically thin nano-materials with controlled pore density and edge sites, such as filtration, electrocatalysis, and sensing.

Highly Enhanced Photoluminescence of Monolayer MoS2 in Plasmonic Hybrids with Double-Layer Stacked Ag Nanoparticles

“…Moreover, the remarkable enhancement of the A 0 peak for the hybrids with double-layer Ag SPs observed in our work can be attributed to the p-doping of MoS 2 induced by thermal annealing. , As reported in the previous literature, the trion recombination is dominant due to the excess electrons in the n-type MoS 2 . , During the RTA process for creating the second layer Ag SPs, depletion of S atoms occurred in the MoS 2 layer, resulting in an increased p-doping in MoS 2 . Further, for the sandwich-like hybrid with the inserted Al 2 O 3 layer, the charge exchange between MoS 2 and Al 2 O 3 interfaces improved the conversion of the A – trion into the neutral A 0 exciton, resulting in the blue shift of the PL peak. , …”

“…Therefore, as a result of the continuous enhancement of the A 0 exciton, the maximum intensity of the PL emission for the plasmonic hybrids shifted from 684 to 659 nm (see Figure 4). 41,42 Zeng and co-workers observed a blue shift of the PL peak of the hybrid constructed by transferring monolayer MoS 2 to Au NPs, which was attributed to the coupling of surface plasmon and exciton. 16 Moreover, the remarkable enhancement of the A 0 peak for the hybrids with double-layer Ag SPs observed in our work can be attributed to the p-doping of MoS 2 induced by thermal annealing.…”

“…Therefore, as a result of the continuous enhancement of the A 0 exciton, the maximum intensity of the PL emission for the plasmonic hybrids shifted from 684 to 659 nm (see Figure ). , Zeng and co-workers observed a blue shift of the PL peak of the hybrid constructed by transferring monolayer MoS 2 to Au NPs, which was attributed to the coupling of surface plasmon and exciton …”

“…16 Moreover, the remarkable enhancement of the A 0 peak for the hybrids with double-layer Ag SPs observed in our work can be attributed to the p-doping of MoS 2 induced by thermal annealing. 41,43 As reported in the previous literature, the trion recombination is dominant due to the excess electrons in the n-type MoS 2 . 44,45 During the RTA process for creating the second layer Ag SPs, depletion of S atoms occurred in the MoS 2 layer, resulting in an increased p-doping in MoS 2 .…”

Plasma Processing and Treatment of 2D Transition Metal Dichalcogenides: Tuning Properties and Defect Engineering

“…As a result, the surrounding atoms are more reactive toward target molecules, leading to enhanced catalytic activity. These defects also increase surface charge separation efficiency due to the reduced migrating paths of charge carriers. − Importantly, the surface distortions can enhance the thermodynamic stability of 2D TMDs as a result of changes in the bond angle, bond length, coordination number, and interatomic distances . Plasma treatment can also induce roughened edges, quasi-ordered chained surface damages, and secondary phases (such as metal oxides).…”