Particle velocities at the complex solids laser ablation in vacuum and in gas ambients

The comparative study of the laser ablated Y–Ba–Cu–O high Tc superconductor, PbTe(Ga) semiconductor and Sn(Cu) metallic alloy has been carried out using a YAG:Nd3+ Q-switched laser, an electrostatic probe and OMA in a region of laser power up to 4.8 J/cm2 and in a region of argon or oxygen pressure up to 0.5 Torr. Ion and electron velocity distributions have been obtained from the probe measurements. Vapor composition and temperature were studied from optical emission spectra. The neutral particle velocity distributions have been calculated from TOF QMS measurements for PbTe(Ga) reported earlier. Two fluxes of the charged particles exist in the region of p=20–100 mTorr: the flux of slow ions and electrons scattered onto the gas molecules, and the flux of the fast non-scattered particles. The position of the ion peaks on the time scale and the average cross section of the scattering in a gas depended on the target material.