  Coupling single photon emitters to surface plasmons provides a versatile
ground for on chip quantum photonics. However, achieving good coupling
efficiency requires precise alignment of both the position and dipole
orientation of the emitter relative to the plasmonic mode. We demonstrate
coupling of single emitters in the 2-D semiconductor, WSe2 self-aligned with
propagating surface plasmon polaritons in silver-air-silver,
metal-insulator-metal waveguides. The waveguide produces strain induced defects
in the monolayer which are close to the surface plasmon mode with favorable
dipole orientations for optimal coupling. We measure an average enhancement in
the rate of spontaneous emission by a factor of 1.89 for coupling the single
defects to the plasmonic waveguide. This architecture provides an efficient way
of coupling single photon emitters to propagating plasmons which is an
important step towards realizing active plasmonic circuits on chip.
