Molecular dynamics studies of ultrafast laser-induced phase and structural change in crystalline silicon
نویسندگان
چکیده
In this work, thermodynamic phenomena in crystalline silicon irradiated by an ultrafast laser pulse were studied using the method of molecular dynamics simulations. The Stillinger–Weber potential was used to model the crystalline silicon. The temperature development in silicon when heated by an ultrafast laser pulse was tracked. Melting and resolidification processes and the resulting structural change were investigated. Radial Distribution Functions were used to track the liquid-amorphous interface during resolidification. It was found that the temperature at the solid–liquid interface could deviate from the equilibrium melting temperature by several hundred degrees. After the melted layer was solidified, some melted material became crystalline and the rest of the material remained in an amorphous state. The difference in the final state was associated with the rate of resolidification and both of the qualitative and quantitative analyses of the relationship between the final atom structure and resolidification rate were
منابع مشابه
Dynamics of Ultrafast Phase Changes in Amorphous GeSb Films
The existence of nonthermal, ultrafast phase transitions after strong femtosecond laser excitation has been demonstrated in several materials such as silicon [1–3], gallium arsenide [3–6], indium antimonide [7], and carbon [8]. It is accepted that such transitions are induced by a softening of the lattice structure due to the generation of a very high density electron-hole plasma, as first prop...
متن کاملCapturing Structural Dynamics in Crystalline Silicon Using Chirped Electrons from a Laser Wakefield Accelerator
Recent progress in laser wakefield acceleration has led to the emergence of a new generation of electron and X-ray sources that may have enormous benefits for ultrafast science. These novel sources promise to become indispensable tools for the investigation of structural dynamics on the femtosecond time scale, with spatial resolution on the atomic scale. Here, we demonstrate the use of laser-wa...
متن کاملInfluence of Interface Thermal Resistance on Relaxation Dynamics of Metal-Dielectric Nanocomposite Materials under Ultrafast Pulse Laser Excitation
Nanocomposite materials, including noble metal nanoparticles embedded in a dielectric host medium, are interesting because of their optical properties linked to surface plasmon resonance phenomena. For studding of nonlinear optical properties and/or energy transfer process, these materials may be excited by ultrashort pulse laser with a temporal width varying from some femtoseconds to some hund...
متن کاملUltrafast Generation of Unconventional {001} Loops in Si.
Ultrafast laser annealing of ion implanted Si has led to thermodynamically unexpected large {001} self-interstitial loops, and the failure of Ostwald ripening models for describing self-interstitial cluster growth. We have carried out molecular dynamics simulations in combination with focused experiments in order to demonstrate that at temperatures close to the melting point, self-interstitial ...
متن کاملModified Enthalpy Method Applied to Laser Annealing of Semi Conductor Films
The rapid melting of silicon film due to the absorption of a CW laser beam radiation is studied. The silicon film melting and recrystallization is mainly controlled by the temperature distribution in the semiconductor. The enthalpy technique for the solution of phase change problems is used in an explicit finite difference form to calculate the transient temperature distribution in the silicon ...
متن کامل