Pustaka Ilmiah Universitas Padjadjaran

Abstrak

Atomistic Study Of Material Dynamics Induced By Laser And Ion Irradiation

Laser assisted material processing has been used since decades ago. This method is one of the most popular techniques, and one of the promising tools to improve the technology of nano-scale device engineering. Laser ablation is a method to remove material by means of photon energy absorption. The application spreads in a very wide area in medical and engineering, such as tissue- or materialremoval and material processing. However the study of the mechanism of laser-material interaction is still ongoing and the underlying theory has not completely been explored. Using the short pulse laser in femto-second pulse-width range, it is possible to probe experimentally the material responses in extremely short time duration (pico- to nano-seconds). This allows the detailed study of responses and gives one to one comparison between theoretical predictions and experiment results. However the initial processes take part at short time in tens to hundreds of femto-seconds after the laser irradiation is not completely known. Another energy source that is also common for surface nano-machining is the ion-beam. In this case the ion is bombarding the surface, and the amount of deposited energy characterize the pattern on surface. The surface morphology is related to the type of bombarding ion, the fluence, and the geometrical configuration of ion beam, that is the angle of incidence. The potential application of ion beam for nano-lithography promising. Nowadays, the popular method is using the so-called Focused-Ion-Beam (FIB). In this proposal we focus to study the processes of material at pico-second time scale using computer simulation methods and longer time scale using Smoothed-Particle-Hydrodynamics method. A so-called Two Temperature Model (TTM) has made an accurate computer simulation of the laser-material interaction possible, by coupling the electronic and lattice temperatures. The method has been used to simulate realistic material responses such as ablation mechanism, void formation and Coulomb explosion of material by high intensity laser pulses, as well as the Swift Heavy Ion. The yearly plan of the proposed research is the following; In the first year we will start with theoretical study and modeling of electron dynamics. The electron will be approached from two approximations: the thermal diffusion model and the fluid flow model. In the second year, we will do the hydro-dynamics study of sputtering and pattern formation on surface. In this stage we plan to start comparing the theoretical observation with experiment data of surface nano-patterns. In the third year we will concentrate in further analysis of surface structures. In this stage we will have all the programming tools needed to simulate systems with various configurations.