Strain-generated single photon emitters in transition-metal dichalcogenide nanoribbons

Chemical vapor deposition (CVD) grown nanoribbons of 2D semiconductors have a reduced geometry that yields distinct structural and electronic properties from 2D crystallites. Here, strain-induced exciton localization and the formation of single photon emitters in nanoribbons of single-layer (1L) WSe₂ and MoS₂ draped over arrays of nanoscale gold cones are investigated. For both systems, the localized strain generates quantum dot-like emitters that blink and spectrally diffuse at cryogenic temperatures. The emitters in the 1L-MoS₂ nanoribbons are dim and have linewidths of about 10 meV. In contrast, the emitters in the 1L-WSe₂ nanoribbons are substantially brighter, have emission linewidths of about 1 meV, and show anti-bunched emission with photon purities nearing 90%. The nanoribbon geometry facilitates correlated atomic force microscopy. It confirms that quantum dot-like states in both systems are localized to regions where an underlying nanocone strains the nanoribbons. Qualitative comparison to 2D crystallites indicates that the reduced geometry of the nanoribbons alters the localized strain induced by the nanocone, providing new insight into the role of microscopic strain in the formation of single photon emitters. These studies reveal how nanoribbons could serve as nanoscale quantum light sources that benefit from the reduced dimensionality of the quasi-1D structure.