Sulfur reduction in MoSO composite towards fabrication of porous structures: physical and nonlinear optical effects

Thin films with high surface-to-volume ratio play a vital role in energy, catalyst and sensor technologies. Although various methods have been developed to produce porous structures, the precise control of the microstructure designs is still lacking. Here, we produced planar flower- and rod-like structures of MoO 3 out of a MoS 2 -MoO 2 -MoO 3 composite thin film by partial removal of its constitutes at high temperatures. The rod sizes were reduced by increasing the thickness of the starting composite layer. At lower thicknesses the produced microstructures became flower-like with a planar structure. Besides, by increasing the thickness of the starting composite layer, the optical bandgap of the samples decreased from 3.7 to 3.2 eV. Moreover, nonlinear optical measurement shows that nonlinear absorption and nonlinear refractive index of MoO 3 /FTO are 1.4 × 10 –6 m 2 W −1 and 5.4 × 10 −5 cm W −1 , respectively.