De-Wrinkling of the 2D Black Phosphorus Using Electron Beam Irradiation

The two dimensional van der waals nanomaterials are sensitive to formation of surface corrugations (wrinkles and ripples) during the handling of materials in any scientific experiment. Especially, Black Phosphorous (BP) is affected by formation of such surface corrugations due to their high surface reactivity. The interface disorders such as interface coulomb contaminations, charge traps and local fluctuations in strain, polarised carrier puddles, dielectric screening and suppression of electron transport occur due to such surface corrugations. While numerous efforts have been made to de- wrinkle the flake, the issue is far from resolved. Here, we demostraste the de wrinkling process that utilizes electron beam of transmission electron microscope (TEM) for ironing out the wrinkles and ripples of BP flake. Experimental outcomes show the enhancement in crystallinity of the flake under e-beam irradiation due to the evolution of lattice ridden with line defects and declinations into the uniformly spaced parallel lattice planes. The overexposure to e-beam causes buckling of flake and thus the de- wrinkling process is optimized by crucially controlling the electron fluence rates or the exposure time. The hitherto undeveloped electron beam based de-wrinkling of 2D flakes with nanoscale precision is prospective to open up innovative prospects for progress of 2D nanomaterials with reproducible optoelectronic properties.