Two-dimensional (2D) materials and their van der Waals (vdW) heterostructures continue to reveal unconventional electronic, optical, and magnetic phenomena closely tied to their dimensionality. In the first part of this thesis, we have demonstrated a facile method for producing uniform, large-area, and crack-free single-crystal transition metal dichalcogenide (TMD) monolayers and artificial structures: wafer-bonder-assisted transfer (WBAT). Compared with single-crystal monolayers produced via traditional Scotch tape exfoliation, the WBAT method can produce flakes that are larger in area by > 10^6 times with almost no cracks. In the second part, we focus on the creation of single photon emitters in the WSe2 and WS2 thin flakes, with defect and strain engineering. Our results show a nearly ideal single-photon purity with g^2(0) = 0.03 through effective spectral background suppression.