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Facile Resist‐Free Nanopatterning of Monolayers of MoS 2 by Focused Ion‐Beam Milling
Author(s) -
Mupparapu Rajeshkumar,
Steinert Michael,
George Antony,
Tang Zian,
Turchanin Andrey,
Pertsch Thomas,
Staude Isabelle
Publication year - 2020
Publication title -
advanced materials interfaces
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.671
H-Index - 65
ISSN - 2196-7350
DOI - 10.1002/admi.202000858
Subject(s) - materials science , monolayer , raman spectroscopy , nanolithography , optoelectronics , focused ion beam , nanoscopic scale , ion beam , photoluminescence , nanotechnology , nanophotonics , photonics , chemical vapor deposition , nanostructure , resist , polarization (electrochemistry) , ion , optics , fabrication , chemistry , medicine , physics , alternative medicine , organic chemistry , pathology , layer (electronics)
Nanopatterning of monolayers of transition metal dichalcogenides offers a new avenue for the creation of nanoscale light sources and their integration into hybrid nanophotonic systems. Here, focused gallium ion‐beam milling is employed as a resist‐free and simple nanofabrication approach to pattern MoS 2 monolayers grown by chemical vapor deposition into nanoribbons. Using photoluminescence (PL), Raman, and valley polarization spectroscopy, it is investigated how the optoelectronic properties of the MoS 2 monolayers are affected by the nanopatterning as a function of the ion fluence used for milling. Characteristic spectral shifts in the Raman and PL peaks are observed, which are indicative of a release of strain in patterned MoS 2 monolayers as compared to the as‐grown monolayers. Furthermore, while the total PL signal is reduced in the patterned monolayers, using circular‐polarization‐resolved cryogenic PL spectroscopy it is shown that the valley polarization is well preserved for monolayers patterned within an optimal ion‐fluence range. The results and in particular the observed robustness of the valley polarization indicate that focused ion‐beam nanopatterned MoS 2 monolayers are interesting candidates for their integration into hybrid quantum systems consisting of designed photonic nanostructures and precisely placed nanoscale excitonic light sources.