Thickness-dependent patterning of MoS2 sheets with well-oriented triangular pits by heating in air

Mo-O bond doping and related-defect assisted enhancement of photoluminescence in monolayer MoS2

“…As reported that MoS 2 will be decomposed during the annealing treatment in air at 300 • C, and sulfide vacancies will be created. 17,18 It is also well known that vacancies in the basal plane and edges of the MoS 2 have high catalytic activity for oxygen and water chemisorption at room temperature. 19 Oxygen and water molecules in air can be adsorbed by the defective sites forming Mo-O bonds under this condition, which can lead to p-doping effect in the MoS 2 film.…”

Edge structures and properties of triangular antidots in single-layer MoS2

“…These results agree well with previous experimental observations that the edges are of ZZ Mo type. 33,34 Furthermore, based on our findings, the experimental edges are likely to have 100% O coverage and to exhibit O dimer termination in the O-rich environment.…”

“…2, indicating that it is feasible to create them by heating MoS 2 in air. 33,34 The 50%-I configuration is energetically favorable over the 50%-II configuration, which is rationalized by much stronger Mo-O bonding both at the corners and along the edges: The average Mo-O bond lengths of 1.91 Å (corners) and 1.72 Å (edges) in the 50%-I configuration are much shorter than the corresponding values of 2.18 Å and 1.97 Å in the 50%-II configuration. Bader charge analysis, 40 which is an effective tool to calculate the charge on individual atoms in molecules as well as crystals, indicates that both the corner and edge Mo atoms lose more charge in the 50%-I configuration, which lowers the total energy.…”

“…Recent experiments have introduced a strategy to fabricate internal edges, i.e., antidots, by heating MoS 2 films in air. 33,34 However, the exact edge structures have not yet been determined, while there exist pioneering theoretical studies exploring the electronic and magnetic properties of the antidots. 35,36 Uncovering the edge morphology and properties of the antidots can provide new insights into ways to tailor the carrier type, Fermi level (E F ), and catalytic activity.…”

“…We note that the theoretical results in this work are based on freestanding single-layer MoS 2 and do not consider the substrate effects present in the experiment. Nonetheless, the interaction between singlelayer MoS 2 and the substrate, such as SiO 2 /Si, 33,34 is mainly of van der Waals type 41 and thus has little effect on the edge energies of the antidots. Figure 3 displays the edge energy as a function of Fig.…”