Design of graphene-like nanowall arrays and their optical absorption properties

Abstract. Bulk-layered materials were constructed into nanowall arrays, and their optical absorption properties were investigated by the finite-difference time-domain technique. The results showed that the nanowall array exhibits excellent absorption properties in both ultraviolet and visible bands. For WS2, MoS2, WSe2, MoSe2, and MoTe2, when the excitation wavelength increases to a certain value, the absorption begins to obviously decrease, and the corresponding excitation wavelength shows a redshift trend. However, the absorptivity of graphene nanowall arrays remains above 0.9 in the 350- to 1200-nm band. In addition, with similar structural parameters, the absorption properties of nanowall arrays are better than those of nanorod arrays. The change in the structural parameter and morphology can lead to an increase in the pore number, specific surface area, and multistage reflection and achieve optical absorption enhancement. Graphene nanowall arrays show excellent absorption properties by our experimental measurement.