Facile fabrication of Au nanoinversions for single photon emission in 2D materials

Monolayer transition metal dichalcogenides (1L-TMD) are 2D materials that host intense light matter interactions. Strained monolayer flakes at 4K are known to exhibit quantum states of light called single photon emitters (SPEs). These SPEs have garnered immense interest in the community leading to various platforms for strain generation used to study and eventually harness SPE applications in quantum communication, information, and computing. One such platform is nanoindentation. In nanoindentation, an AFM tip is pressed into a 1L-TMD on a polymethyl methacrylate (PMMA) substrate causing plastic deformation in the PMMA and a strain center in the 1L-TMD. The indentation platform gives deterministic placement of strain but can be difficult and ambiguous to characterize due to the strain being isolated within a cavity. To address this, we report a facile fabrication technique for the inversion of indents by back filling with Au and adhering a new primary substrate for template stripping. Nanoinversion enables both structural characterization of the 2D material with AFM and SEM and optical characterization of bright SPE states using 4K photoluminescence spectroscopy when a dielectric buffer layer is present between the 1L-TMD and the Au.