Enhancing exciton diffusion in monolayer W S2 with h -BN bottom layer
Abstract
We investigated two-dimensional (2D) exciton diffusion in monolayer W S2 on both Si O2 and hexagonal boron nitride (h -BN ) layers to identify the exciton diffusion enhanced by the h -BN bottom layer using spatially resolved photoluminescence imaging combined with time-resolved spectroscopy. The W S2 on the h -BN bottom layer shows an exciton diffusion coefficient of 38 c m2/s , which is almost 1.7 times that of W S2 on the Si O2 layer. Electrostatic force microscopy confirms that the increase in the 2D exciton diffusion is mainly due to the reduction in the charge impurities and traps on the h -BN surface compared to the Si O2 surface.
- Publication:
-
Physical Review B
- Pub Date:
- November 2019
- DOI:
- 10.1103/PhysRevB.100.205304
- Bibcode:
- 2019PhRvB.100t5304K