  Assembly of quantum nanophotonic systems with plasmonic resonators are
important for fundamental studies of single photon sources as well as for
on-chip information processing. In this work, we demonstrate controllable
nanoassembly of gold nanospheres with ultra-bright quantum emitters in 2D
layered hexagonal boron nitride (hBN). We utilize an atomic force microscope
(AFM) tip to precisely position gold nanospheres to close proximity of the
quantum emitters and observe the resulting emission enhancement and
fluorescence lifetime reduction. A fluorescence enhancement of over 300% is
achieved experimentally for quantum emitters in hBN, with a radiative quantum
efficiency of up to 40% and a saturated count rate in excess of 5 million
counts/s. Our results are promising for future employment of quantum emitters
in hBN for integrated nanophotonic devices and plasmonic based nanosensors.
