Highly linear polarized photoluminescence from a rippled WSe₂ monolayer

Shaping the topography of an atomically thin film is a novel way to engineer the optoelectronic performances of an ideal surface. In this letter, we study the photoluminescence characters of a WSe₂ monolayer of spiky nanostructures and rippled morphology, which are induced during the transfer process of monolayer to a Bi₂Se₃ flake. Photo-excited excitons are trapped by these nanostructures, resulting in energy redshifts up to 150 meV at low temperature. We study the polarization degrees of the corresponding radiation signals and the polarization directions. Interestingly, the appearance features of monolayer correlates with the optical polarization property of the photoluminescence. Our work attracts insight to the relevance between surface topography and the dipole polarization on an ideal surface.