Exploring ablation of GaAs at atomic and close-to-atomic scale by pulsed laser and 3D TTM-MD simulations

Pulsed laser technology offers significant advantages in atomic and closed-to-atomic scale manufacturing due to its high-resolution capabilities in non-contact fabrication as well as its high-efficiency and low-cost. Pulsed laser irradiation experiments on a GaAs surface were conducted to study ablation and atomic-level modification. A three-dimensional two-temperature model, combined with the molecular dynamics (3D TTM-MD) method, was developed to investigate the mechanisms responsible for the material removal and surface modification during pulsed laser irradiation. Results show that phase explosion is the main mechanism for material removal at high fluences, leading to explosively decomposed into a two-phase mixture of liquid and vapor. As fluence increases, the proportion of vapor component rises, while amorphization becomes dominate near the damage threshold fluences. This work reveals the atomic dynamics of GaAs under varying laser fluences, offering valuable insights for laser processing towards to the atomic and close-to-atomic scale.