Exploring the surface oxidation and environmental instability of 2H-/1T’-MoTe2 using field emission based scanning probe lithography

An unconventional approach for the resistless nanopatterning 2H- and 1T’-MoTe₂ by means of scanning probe lithography is presented. A Fowler–Nordheim tunneling current of low energetic electrons (E = 30–60 eV) emitted from the tip of an atomic force microscopy (AFM) cantilever is utilized to induce a nanoscale oxidation on a MoTe₂ nanosheet surface under ambient conditions. Due to the water solubility of the generated oxide, a direct pattern transfer into the MoTe₂ surface can be achieved by a simple immersion of the sample in deionized water. The tip-grown oxide is characterized using Auger electron and Raman spectroscopy, revealing it consists of amorphous MoO₃/MoO_x as well as TeO₂/TeO_x. With the presented technology in combination with subsequent AFM imaging it is possible to demonstrate a strong anisotropic sensitivity of 1T’-/(T_d)-MoTe₂ to aqueous environments. Finally the discussed approach is used to structure a nanoribbon field effect transistor out of a few-layer 2H-MoTe₂ nanosheet.