Apr 11, 2025
10:30am - 10:45am
Summit, Level 4, Room 444
John Fix1,Joseph Stage1,Andrew Lingley1,Nicholas Borys1
Montana State University1
John Fix1,Joseph Stage1,Andrew Lingley1,Nicholas Borys1
Montana State University1
Single-layer (1L) transition metal dichalcogenide (TMD) semiconductors are rich platforms for studying single-photon emitters (SPEs). SPEs are atom-like states embedded in solid-state materials that emit one photon at a time in a narrow energy band on the order of a µeV. In 1L-WSe
2, SPEs form in regions of localized of tensile strain. One method to create localized strain is through nano-indentation using an atomic force microscope tip. It has long been assumed that the TMD must not rip or tear during the nanoindentation process to reliably observe the formation of SPE states. In this work, we test this hypothesis in nano-indented 1L-WSe
2 and 1L-WS
2 crystallites. Using room-temperature photoluminescence and combined AFM and SEM structural characterization, we are able to unambiguously determine whether the TMD is ripped at the indentation site. When the TMD is locally strained by the indent, the room temperature photoluminescence is systematically broadened and shifted to lower energy. In systems where the TMD is ripped, no such changes are observed which suggests that the ripping relaxes the tensile strain. At cryogenic temperatures, however, bright SPEs states are observed for both the ripped and strained indentation sites. The presence of tears that is inferred from the room temperature spectroscopy is directly confirmed by SEM and AFM characterization of the indents that have been inverted to pyramid structures. Our study has established an unambiguous method to determine if the material at the indentation site is ripped or strained and has enabled the demonstration that SPEs are present in the indents, whether the TMD is ripped or not.