Interfacial Properties of Monolayer SnS–Metal Contacts

Two-dimensional semiconducting SnS is expected to have great potential for application in nanoelectronics. By using both ab initio electronic structure calculations and more reliable quantum transport simulations, we systematically explored the interfacial properties of monolayer (ML) SnS in contact with a series of metals (Ag, Al, Au, Pd, Cu, and Ni) for the first time. According to the adsorption level, three categories are found: strong adsorption is found in ML SnS–Pd and Ni contacts; medium adsorption is found in ML SnS–Cu contacts; and weak adsorption is found in ML SnS–Ag, Al, and Au contacts. Because the band structure of ML SnS is destroyed in all of the contact systems, a vertical Schottky barrier at the ML SnS–metal interface is absent. However, at the metalized-SnS/uncontacted-SnS interface in a transistor configuration, a lateral Schottky contact is always formed as a result of strong Fermi level pinning (with a pinning factor of 0.17–0.28) according to the quantum transport simulations. This work provides guidelines to design ML SnS-based devices with optimized electrode contact for high performance

Few-Layer Fe₃(PO₄)₂·8H₂O: Novel H‑Bonded 2D Material and Its Abnormal Electronic Properties

Using first-principles calculations, we study the structural and electronic properties of a new layered hydrogen-bonded 2D material Fe₃(PO₄)₂·8H₂O. Interestingly, unlike other common 2D materials, such as layered van der Waals 2D materials, the band gap of 2D Fe₃(PO₄)₂·8H₂O-(010)-(1 × 1) is smaller than bulk Fe₃(PO₄)₂·8H₂O, which does not obey the normal quantum confinement effect and can be attributed to the edge states and the hydrogen bonds between the layers. We also find that the band-gap variation with the reduced layers depends on the length of the interlayer hydrogen bond and the stronger interlayer hydrogen bond leads to the larger band gap