Nano-wrinkle induced room-temperature exciton localization in monolayer WSe₂

The field of quantum information science promises to usher in the next age of technological breakthroughs. In order to do so, more work needs to be done on fundamental components of quantum systems. One such crucial element is the single-photon source (SPS). Many diverse systems—from quantum dots to nitrogen-vacancy color centers in diamond—have been shown to host SPSs; however, these typically require cryogenic temperature to operate, lack tunability, or are hard to integrate with other components. Herein we examine an alternative solid-state system based on highly strained monolayer sheets of WSe2, which has the potential to host tunable SPSs at room temperature. The single crystal nature and extremely low defect density of this van der Waals material allows it to tightly conform to sharp substrate features without breaking. Instead, nanoscale wrinkles are formed in the sheet, emanating from, and in some cases bridging the patterned structures. Following our recent work on strained nanobubbles, we show that these highly strained regions can effectively localize excitons in the material and produce low-energy emission observable at room temperature, which is consistent with the location of SPSs reported in cryogenic studies.