Evidence for the formation of metallic In after laser irradiation of InP

Abstract

Structural and electronic changes induced by laser irradiation are currently of interest owing to the possibility to tune the mechanical, optical, and transport properties of the irradiated materials. In this work, we investigate the effects of laser irradiation on indium phosphide, InP, by modifying the electronic temperature, Te, of the system within the density functional theory framework and performing molecular dynamics simulations to prove that the laser irradiation also provokes a local thermalization effect. We found that the process can be described by a two-stage mechanism. First, at low Te values (0–1.0 eV), the laser energy induces electronic transitions, while the InP lattice remains undisturbed and cool. In the second stage (with Te in the range of 1.0–4.0 eV), both electron-electron scattering and electron-phonon coupling processes are triggered, increasing the energy of the lattice so as to provoke a Coulomb explosion, which changes some physical chemical properties of InP. The close agreement between the simulations helps explain the formation of metallic In as it is observed in the transmission electron microscopy images.