Room-Temperature Patterning of Nanoscale MoS 2 under an Electron Beam

• Published in: ACS applied materials & interfaces Vol. 12; no. 14; pp. 16772 - 16781
• Main Authors: Saifullah, Mohammad S M, Asbahi, Mohamed, Binti-Kamran Kiyani, Maryam, Liow, Sing Shy, Bin Dolmanan, Surani, Yong, Anna Marie, Ong, Esther A H, Ibn Saifullah, Asadullah, Tan, Hui Ru, Dwivedi, Neeraj, Dutta, Tanmay, Ganesan, Ramakrishnan, Valiyaveettil, Suresh, Chong, Karen S L, Tripathy, Sudhiranjan
• Format: Journal Article
• Language: English
• Published: United States 08.04.2020
• Subjects: single-source precursors; nanofabrication; xanthates; molybdenum disulfide; electron beam lithography; resists; molybdenum thiocubane
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.9b22229

Molybdenum disulfide (MoS ) is traditionally grown at a high temperature and subsequently patterned to study its electronic properties or make devices. This method imposes severe limitations on the shape and size of MoS crystals that can be patterned precisely at required positions. Here, we describe a method of direct nanoscale patterning of MoS at room temperature by exposing a molybdenum thiocubane single-source precursor to a beam of electrons. Molybdenum thiocubanes with various alkylxanthate moieties [Mo S (ROCS ) , where R = alkyl] were prepared using a "self-assembly" approach. Micro-Raman and micro-FTIR spectroscopic studies suggest that exposure to a relatively smaller dose of electrons results in the breakdown of xanthate moieties, leading to the formation of MoS . High-resolution transmission electron micrographs suggest that the growth of MoS most likely happens along (100) planes. An electron-beam-induced chemical transformation of a molybdenum thiocubane resist was exploited to fabricate sub-10 nm MoS lines and dense dots as small as 13 nm with a pitch of 33 nm. Since this technique does not require the liftoff and etching steps, patterning of MoS with interesting shapes, sizes, and thicknesses potentially leading to tunable band gap is possible.