Elongation rate measurements of nanofilms by microbump method induced by laser pulse

A laser pulse-induced microbump method that aims to measure the elongation rate of nanofilms is proposed. The sample structure is designed as “substrate/active layer/nanofilm” and the laser pulse is used as energy source to heat the active layer and to create microbump. These cause the nanofilm to expand and elongate. The surface area and length change of nanofilm is calculated by measuring the deflections and diameters of the microbumps, as well as to obtain the elongation rate of the nanofilms. A series of microbumps with different deflections are obtained. The deflections are measured precisely by atomic force microscopy (AFM) by taking AgO_x and ZnS-SiO₂ as the active layer and nanofilm, respectively, and by controlling pulse laser parameters. The line elongation rate and plane elongation rate of ZnS-SiO₂ nanofilm are measured at thickness of only 10 nm. Results show that both the two elongation rates linearly increases with laser power from 3.2 to 5.2 mW. Plane elongation rate is a little higher than the line elongation rate at the same laser power. The rupture at 5.4 mW laser power corresponds to fracture strength of the film. The maximum line elongation rate and plane elongation rate are 13.241% and 19.766%, respectively. This method applies a reproducible and efficient method for its applications in the near future.