Papers by Author: Cheng Kuo Sung

Abstract: Molecular dynamics (MD) simulation and the experiment of adhesion force measurement were introduced to study the nanostructure formation process in the atomic force microscopy. The atomic level process of the nanostructure formation and the thermo-mechanical effect caused by the factors of the contact area, the adhesion force, and the temperature were clearly shown and discussed. The size of the forming nanostructures was found to be positively related to the contact area and temperature, but the adhesion force would decrease as the temperature increase. In the case of higher temperature with smaller adhesion force, however, the larger-size nanostructure could still be made.

Abstract: The nanoimprinting process between a nickel mold and a gold thin film consisting of 9500 – 11000 atoms was studied using molecular dynamics computational simulation. The nickel mold and the gold thin film were both formed in face central cubical (FCC) single crystal, and the simulation condition was in an isothermal state of 300K. The Morse potential was utilized in order to determine interatomic forces and potentials. During the nanoimprinting process, jump-to-contact, thin-film recovery, slip-line like, dead-metal zone and dislocation phenomena were observed. After finishing nanoimprinting processes, the interactive force curves between the mold pattern and thin film, and those inside the thin film were measured. By varying the pattern width of the mold and incorporating the measured force curves inside the thin film, the length effect on metallic pattern formation can be determined. In addition, through analytical investigation, it can be observed that the thin-film thickness, the pattern width of the mold, and the applied force should be matched up very well in order to obtain good formation of metallic pattern.