Nanopatterning and Electrical Tuning of MoS2 Layers with a Subnanometer Helium Ion Beam

• Published in: Nano letters 2015-08, Vol.15 (8), p.5307-5313
• Main Authors: Fox, Daniel S, Zhou, Yangbo, Maguire, Pierce, O’Neill, Arlene, Ó’Coileáin, Cormac, Gatensby, Riley, Glushenkov, Alexey M, Tao, Tao, Duesberg, Georg S, Shvets, Igor V, Abid, Mohamed, Abid, Mourad, Wu, Han-Chun, Chen, Ying, Coleman, Jonathan N, Donegan, John F, Zhang, Hongzhou
• Format: Article
• Language: English
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/acs.nanolett.5b01673

We report subnanometer modification enabled by an ultrafine helium ion beam. By adjusting ion dose and the beam profile, structural defects were controllably introduced in a few-layer molybdenum disulfide (MoS2) sample and its stoichiometry was modified by preferential sputtering of sulfur at a few-nanometer scale. Localized tuning of the resistivity of MoS2 was demonstrated and semiconducting, metallic-like, or insulating material was obtained by irradiation with different doses of He+. Amorphous MoS x with metallic behavior has been demonstrated for the first time. Fabrication of MoS2 nanostructures with 7 nm dimensions and pristine crystal structure was also achieved. The damage at the edges of these nanostructures was typically confined to within 1 nm. Nanoribbons with widths as small as 1 nm were reproducibly fabricated. This nanoscale modification technique is a generalized approach that can be applied to various two-dimensional (2D) materials to produce a new range of 2D metamaterials.