Phase transformation on and charged particle emission from a silicon crystal surface, induced by picosecond laser pulses

Ultrafast melting and resolidification on a (111) sufarce of a silicon crystal wafer, induced by 20-ps pulses at 532-nm wavelength, is accompanied by the emission of charged particles. This emission is studied as a function of pulse energy, in combination with time-resolved reflectivity changes and post-annealing morphology. The data provide evidence that thermalization time for a dense carrier plasma and the lattice is shorter than 10−11 s.