Microwave synthesis of molybdenene from MoS2
Tumesh Kumar Sahu, Nishant Kumar, Sumit Chahal, Rajkumar Jana, Sumana Paul, Moumita Mukherjee, Amir H. Tavabi, Ayan Datta, Rafal E. Dunin‐Borkowski, Ilia Valov, Alpana Nayak, Prashant Kumar
Abstract
Abstract Dirac materials are characterized by the emergence of massless quasiparticles in their low-energy excitation spectrum that obey the Dirac Hamiltonian. Known examples of Dirac materials are topological insulators, d -wave superconductors, graphene, and Weyl and Dirac semimetals, representing a striking range of fundamental properties with potential disruptive applications. However, none of the Dirac materials identified so far shows metallic character. Here, we present evidence for the formation of free-standing molybdenene, a two-dimensional material composed of only Mo atoms. Using MoS 2 as a precursor, we induced electric-field-assisted molybdenene growth under microwave irradiation. We observe the formation of millimetre-long whiskers following screw-dislocation growth, consisting of weakly bonded molybdenene sheets, which, upon exfoliation, show metallic character, with an electrical conductivity of ~940 S m −1 . Molybdenene when hybridized with two-dimensional h-BN or MoS 2 , fetch tunable optical and electronic properties. As a proof of principle, we also demonstrate applications of molybdenene as a surface-enhanced Raman spectroscopy platform for molecular sensing, as a substrate for electron imaging and as a scanning probe microscope cantilever.