INTERACTIONS OF WIDE BAND-GAP SINGLE-CRYSTALS WITH 248 NM EXCIMER-LASER RADIATION .2. NACL

The emission of charged and neutral particles from single-crystal NaCl irradiated with 248 nm excimer laser light is studied by means of tim e-resolved photon spectroscopy and quadrupole mass spectrometry. Catho do- and photoluminescence spectra and scanning electron microscope (SE M) observations indicate the progressive growth of surface damage duri ng pulsed laser irradiation. SEM observations indicate that substantia l fracture occurs prior to the onset of rapid vaporization. The plume is composed of charged particles as well as a high density of excited neutrals, including a number of energetic cluster ions. Fracture and s ubsequent plastic deformation contribute significantly to defect produ ction and processes of laser desorption and vaporization.