Voltage-Induced Degradation for Enhanced Purity and Reproducibility of Quantum Emission in Monolayer 2D Materials

We report a voltage-induced degradation technique using conductive atomic force microscopy to enhance the single-photon purity and reproducibility of quantum emitters in monolayer tungsten diselenide (WSe₂). By applying a controlled electric field across a monolayer WSe₂/poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) on a silicon substrate, localized degradation is induced around nanoindented emitter sites in the WSe₂. This process selectively suppresses defect-bound exciton emissions while preserving emission from pristine regions within the indentations. Photoluminescence and second-order correlation measurements at 18 K demonstrate a substantial increase in single-photon purity when comparing emitters from untreated and voltage-treated regions. Emitters from untreated regions showed average values of g²(0) near or above the 0.5 threshold. In contrast, emitters from voltage-treated regions exhibited g²(0) values consistently below 0.14, with most falling near 0.05, demonstrating high-purity single-photon emission well below the g²(0) < 0.5 threshold. Importantly, the voltage-induced degradation method significantly boosts the production yield of high-purity single-photon emitters with g²(0) < 0.2 in over 10% of treated sites─an order of magnitude improvement over typical yield in two-dimensional (2D) materials. This nonvolatile, spatially selective approach enhances both emitter purity and yield without compromising emission intensity, offering a scalable and reliable route for integrating high-quality quantum emitters into photonic platforms. Integration with spectral tuning strategies such as strain engineering, local dielectric patterning, or electrostatic gating could further enable deterministic, wavelength-selective single-photon sources for advanced quantum photonic applications.