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 time-resolved photon spectroscopy and quadrupole mass spectrometry. Cathodo- and photoluminescence spectra and scanning electron microscope (SEM) observations indicate the progressive growth of surface damage during pulsed laser irradiation. SEM observations indicate that substantial 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 subsequent plastic deformation contribute significantly to defect production and processes of laser desorption and vaporization.