Nanosculpting of Atomically Thin 2D Materials for Site‐Specific Photoluminescence Modulation

Abstract

AbstractNanomanufacturing techniques to generate patterned structures of mechanically exfoliated two‐dimensional (2D) materials by lithography, gas phase etching, and electron beam/ion beam irradiation have gained significant interest. Such control over patterning in monolayers of WS2 and MoS2 will aid the development of novel, miniaturized devices for nanoelectronic and nanophotonic applications. In this study a controlled site‐specific nanosculpting of WS2 and MoS2 monolayers grown on SiO2/Si substrate by atmospheric pressure chemical vapor deposition (CVD) is reported. Nanoindentation by sharp diamond Berkovich tip with ≈50 nm radius is used to make periodic arrays of indents to spatially modulate photoluminescence (PL) intensity up to more than an order of changes. To demonstrate systematic strain variation, relatively shallow indentations are also carried out with conical tip of ≈5 µm radius. Raman and PL measurements carried out near the indented region indicate a systematic variation in strain with respect to load and location. Further, nanosculpting to design nonperiodic structures is achieved by performing nanoindentation in close proximity to each other with detailed Raman and PL mapping. The developed approach of indentation‐based site‐specific nanosculpting of 2D materials and modulation of PL intensity provides direct pathways to design a variety of patterned structures and nanoscale devices for photodetector applications.