How Thermal Annealing Process Determines the Inherent Structure Evolution in Amorphous Silicon: An Investigation from Atomistic Time Scales to Experimental Time Scales

Abstract: The annealing treatment in the advanced manufacturing process, e.g., laser-assisted manufacturing, determines the final state of glasses which is critical to its thermal, electrical and mechanical properties. Energy barriers analysis based on the potential energy surface offers an effective way to study the microscopic evolution of the inherent structures during the annealing process in a broadening timescale range, i.e., from atomistic timescale ( ~ ps) to experimental timescale (~ s). Here, we find the distribution activation energy barriers in the potential energy surface can be divided into three regimes 1, the distribution mainly follows the Rayleigh distribution when the annealing rate Rdot < 1e15 K/s; 2, two different modes, i.e., an exponentially decaying mode and a Rayleigh distribution mode, are found in the spectra when the annealing rate 1e15 K/s < Rdot < instant; 3, the spectra is almost following the exponentially decaying mode when the system is under the instant annealing process. However, the spectra of relaxation energy barriers only show an exponentially decaying mode with a decreasing decay parameter. A multi timescale model for any specific annealing rate, which is beyond the limit of the conventional atomistic simulations, i.e., molecular dynamics simulations, is then proposed based on the distribution of the energy barriers. Such a model enables quantitative explanations and predictions of the heat release during the annealing process of the nanocalorimetry measurements or laser-assisted manufacturing.