Modification of 2D-Transition Metal Dichalcogenides by Excess Metal Incorporation

Abstract:

The reduced structural constraints in 2D (van der Waals-) materials enable the incorporation of excess atoms into the 2D-lattice. These excess metals may result in point-, extended- defects, or cause a transformation into new stoichiometric phases. In this talk we discuss different mechanisms to induce compositional variations by reacting transition metal dichalcogenides (TMDs) with metal atoms or by removing chalcogen atoms. Not surprisingly, given the broad nature of the TMDs, different transition metal groups respond differently to metal rich conditions. The early transition metal dichalcogenides (group 5 transition metals) have a preference to insert excess metals in between TMD layers [1,2,3]. Group 6 TMDs may incorporate elements at interstitial sites which may cause restructuring into metal-rich mirror twin grain boundary networks [4,5] that can order into novel phases. In contrast, group 10 PtTe₂ can transform into a different stoichiometric phase, i.e., 2D Pt-monotelluride [6,7,8,9]. Understanding the processes by which TMDs react with excess metals shine light on synthesis processes and point towards methods for modifying or synthesizing novel 2D materials with new desirable functionalities.

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