Inhomogeneity of Cleaved Bulk MoS2 and Compensation of Its Charge Imbalances by Room-Temperature Hydrogen TreatmentShow others and affiliations
2023 (English)In: Advanced Materials Interfaces, ISSN 2196-7350, Vol. 10, no 32, article id 2300392Article in journal (Refereed) Published
Abstract [en]
Synthetic single crystals of bulk molybdenum disulphide cleaved in ultrahigh vacuum are mapped across a large (approximate to 25 mm(2)) area by X-ray photoelectron spectroscopy, both statically and transiently following above-bandgap excitation by an ultrafast laser. This work finds that: I) A cleaved surface typically displays spatially inhomogeneous properties, manifested by large (approximate to 1 eV) variations in binding energy and band bending and variable degrees of stability of those over time as a result of variable gas uptakes from the residual atmosphere. II) Moderate (350 degrees C) annealing and exposure to molecular hydrogen can be cycled to switch between smaller and larger surface band bending, the switch being reversible but strongly sample-position dependent. III) Upon exposure to atomic hydrogen, the binding energy of the entire surface levels out to a common (within <0.05 eV) value corresponding to a Fermi level pinned close to mid-bandgap. Such remarkable effect is attributed to the ability of hydrogen atoms to serve as donors and acceptors alike, thus neutralizing local charge imbalances inevitably present at the surface in consequence of intrinsic and/or cleavage-induced defects. With subsequent moderate annealing, the hydrogenated surface preserves a fairly homogenous electronic state which is however characterized by a lower binding energy and little to no band bending.
Place, publisher, year, edition, pages
Wiley , 2023. Vol. 10, no 32, article id 2300392
Keywords [en]
molybdenum disulphide, sample inhomogeneity, hydrogen adsorption, surface passivation, transition metal dichalcogenides
National Category
Chemical Engineering
Identifiers
URN: urn:nbn:se:kth:diva-337712DOI: 10.1002/admi.202300392ISI: 001059141900001Scopus ID: 2-s2.0-85169320539OAI: oai:DiVA.org:kth-337712DiVA, id: diva2:1803298
Note
QC 20231009
2023-10-092023-10-092025-03-27Bibliographically approved