caa a22 4500 463212584 CHVBK 20180405153146.0 cr unu---uuuuu 170326e20071001xx s 000 0 eng 10.1007/s00339-007-4197-0 doi (NATIONALLICENCE)springer-10.1007/s00339-007-4197-0 Examination of the laser-induced variations in the chemical etch rate of a photosensitive glass ceramic [Elektronische Daten] [F.E. Livingston, P.M. Adams, H. Helvajian] Previous studies in our laboratory have reported that the chemical etch rate of a commercial photosensitive glass ceramic (FoturanTM, Schott Corp., Germany) in dilute hydrofluoric acid is strongly dependent on the incident laser irradiance during patterning at λ=266nm and λ=355nm. To help elucidate the underlying chemical and physical processes associated with the laser-induced variations in the chemical etch rate, several complimentary techniques were employed at various stages of the UV laser exposure and thermal treatment. X-ray diffraction (XRD) was used to identify the crystalline phases that are formed in Foturan following laser irradiation and annealing, and monitor the crystalline content as a function of laser irradiance at λ=266nm and λ=355nm. The XRD results indicate the nucleation of lithium metasilicate (Li2SiO3) crystals as the exclusive phase following laser irradiation and thermal treatment at temperatures not exceeding 605°C. The XRD studies also show that the Li2SiO3 density increases with increasing laser irradiance and saturates at high laser irradiance. For our thermal treatment protocol, the average Li2SiO3 crystal diameters are 117.0±10.0nm and 91.2±5.8nm for λ=266nm and λ=355nm, respectively. Transmission electron microscopy (TEM) was utilized to examine the microscopic structural features of the lithium metasilicate crystals. The TEM results reveal that the growth of lithium metasilicate crystals proceeds dendritically, and produces Li2SiO3 crystals that are ∼700-1000nm in length for saturation exposures. Optical transmission spectroscopy (OTS) was used to study the growth of metallic silver clusters that act as nucleation sites for the Li2SiO3 crystalline phase. The OTS results show that the (Ag0)x cluster concentration has a dependence on incident laser irradiance that is similar to the etch rate ratios and Li2SiO3 concentration. A comparison between the XRD and optical transmission results and our prior etch rate results show that the etch rate contrast and absolute etch rates are dictated by the Li2SiO3 concentration, which is in turn governed by the (Ag0)x cluster concentration. These results characterize the relationship between the laser exposure and chemical etch rate for Foturan, and permit a more detailed understanding of the photophysical processes that occur in the general class of photostructurable glass ceramic materials. Consequently, these results may also influence the laser processing of other photoactive materials. Springer-Verlag, 2007 Livingston F.E. Micro/Nanotechnology Department, Space Materials Laboratory, The Aerospace Corporation, 2350 E. El Segundo Blvd., 90245-4691, El Segundo, CA, USA aut Adams P.M. Materials Processing and Evaluation Department, Space Materials Laboratory, The Aerospace Corporation, 2350 E. El Segundo Blvd., 90245-4691, El Segundo, CA, USA aut Helvajian H. Micro/Nanotechnology Department, Space Materials Laboratory, The Aerospace Corporation, 2350 E. El Segundo Blvd., 90245-4691, El Segundo, CA, USA aut Applied Physics A Springer-Verlag 89/1(2007-10-01), 97-107 0947-8396 89:1<97 2007 89 339 https://doi.org/10.1007/s00339-007-4197-0 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00339-007-4197-0 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Livingston F.E. Micro/Nanotechnology Department, Space Materials Laboratory, The Aerospace Corporation, 2350 E. El Segundo Blvd., 90245-4691, El Segundo, CA, USA aut NATIONALLICENCE 700 1- Adams P.M. Materials Processing and Evaluation Department, Space Materials Laboratory, The Aerospace Corporation, 2350 E. El Segundo Blvd., 90245-4691, El Segundo, CA, USA aut NATIONALLICENCE 700 1- Helvajian H. Micro/Nanotechnology Department, Space Materials Laboratory, The Aerospace Corporation, 2350 E. El Segundo Blvd., 90245-4691, El Segundo, CA, USA aut NATIONALLICENCE 773 0- Applied Physics A Springer-Verlag 89/1(2007-10-01), 97-107 0947-8396 89:1<97 2007 89 339 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer