Ultrafast laser-induced structural changes in semiconductors


E. Mazur, E. N. Glezer, L. Huang, and J. Paul Callan. 1996. “Ultrafast laser-induced structural changes in semiconductors.” In . 28th Annual Boulder Damage Symposium. Publisher's Version


We present experimentally determined values of dielectric function of GaAs following fs laser excitation. The data at photon energies of 2.2 and 4.4 eV show that the response of the dielectric function to the excitation is dominated by changes in the electronic band structure and not by the optical susceptibility of the excited free carriers. The behavior of the dielectric function indicates a drop in the average bonding-antibonding splitting of GaAs following the excitation, which leads to a collapse of the band gap. The changes in the electronic band structure result from a combination of electronic screening as well as structural deformation of the lattice caused by the destabilization of the covalent bond. The broadband measurement dielectric function from 1.5-3.5 eV reveals the ultrafast laser-induced heating, disordering and semiconductor to metal transition on a picosecond time scale.
Last updated on 07/24/2019