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Physics of monolayer and few-layer transition metal dichalcogenides (TMDs) and chemistry of few-layer TMDs have been well studied in recent years in the context of future electronic, optoelectronic, and energy harvesting applications. However, what has escaped the attention of the scientific community is the unique chemistry of monolayer TMDs. It has been demonstrated that the basal plane of multilayer TMDs is chemically inert, whereas edge sites are chemically active. In this article, we experimentally demonstrate that the edge reactivity of the TMDs can be significantly impeded at the monolayer limit through monolayer/substrate interaction, thus making the monolayers highly resistant to electrooxidation and corrosion. In particular, we found that few-layer flakes of MoS2 and WS2 exfoliated on conductive TiN substrates are readily corroded beyond a certain positive electrode potential, while monolayer remnants are left behind unscathed. The electrooxidation resistance of monolayers was confirmed using a ...

In this paper, we report high-performance monolayer thin-film transistors (TFTs) based on a variety of two-dimensional layered semiconductors such as MoS2, WS2, and MoSe2 which were obtained from their corresponding bulk counterparts via an anomalous but high-yield and low-cost electrochemical corrosion process, also referred to as electro-ablation (EA), at room temperature. These monolayer TFTs demonstrated current ON–OFF ratios in excess of 107 along with ON currents of 120 μA/μm for MoS2, 40 μA/μm for WS2, and 40 μA/μm for MoSe2 which clearly outperform the existing TFT technologies. We found that these monolayers have larger Schottky barriers for electron injection compared to their multilayer counterparts, which is partially compensated by their superior electrostatics and ultra-thin tunnel barriers. We observed an Anderson type semiconductor-to-metal transition in these monolayers and also discussed possible scattering mechanisms that manifest in the temperature dependence of the electron mobility. ...

In this paper we provide insight into an anomalous corrosion process, referred to as electroablation (EA), which converts multilayer flakes of transition metal diselenides like MoSe2 into their corresponding monolayers when micromechanically exfoliated on a conductive electrode and subsequently subjected to a high anodic potential inside a conventional electrochemical cell. Photoluminescence intensity maps and scanning transmission electron microscopy (STEM) images confirmed the single crystalline nature and 2H-hexagonal lattice structure of the remnant monolayer MoSe2 flakes, indicating the superior corrosion stability of the monolayers compared to that of the bulk counterpart. It is noted that the EA technique is a low-cost alternative for high-yield synthesis of single crystalline monolayer MoSe2 at room temperature. We also found that the dynamics of such an electro-oxidation-mediated and self-limiting corrosion process differs significantly for MoSe2 and WSe2. While we were able to engineer the corro...