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Silicon precipitation in a surface layer of SiO2 by high-power vacuum ultraviolet laser irradiation
A57 464
Surface Science 242 (1991) 464-469 North-Holland
Thermal desorption of molecules coadsorbed on metal surfaces M. M i z u n o , H. Kasai and A. Okiji Department of Applied Physics, Osaka University, Suita, Osaka 565, Japan Received 16 May 1990; accepted for publication 13 June 1990 On the basis of the absolute reaction rate theory, the thermal desorption spectra of the coadsorption system, NO + C O / P t ( l l l ) , are calculated with the aid of the lattice gas model. It is shown that the spectra for NO molecules strongly depend on the coverage of preadsorbed CO molecules on a P t ( l l l ) surface. A good account of the experimental results is given for the thermal desorption spectra of NO molecules on a P t ( l l l ) surface with pre-adsorbed CO molecules.
470
Surface Science 242 (1991) 470-474
Molecule-surface complexes and catalytic reactions Ernest Ilisca 1 Research Center for Extreme Materials, Osaka University, Toyonaka, Osaka 560, Japan Received 18 May 1990; accepted for publication 11 June 1990 In physcial molecular adsorption and catalysis the building of surface-molecule complexes incl-des surface symmetries and opens therefore new intra-molecular catalytic channels. We illustrate this general property by investigating the o - p conversion of a hydrogen molecule adsorbed on a cold metal surface. A large family of processes is described with their relevant channels. Their common feature is the metal excitation of electron-hole triplet pairs with hyperfine contact at the H 2 protons. It is concluded that metallic conversion might be as efficient as the magnetic one displayed by insulators, even in the absence of molecular cliemisorption.
Surface Science 242 (1991) 475-480 North-Holland
475
Silicon precipitation in a surface layer of SiO 2 by high-power vacuum ultraviolet laser irradiation K o u K u r o s a w a a, Yasuo Takigawa b, Wataru Sasaki c, Masahiro Okuda a and Yoshihide Inoue d a Department of Electronics, Universityof Osaka Prefecture, Sakai 591, Japan b Department of Solid State Electronics, Osaka Electro-Communication University, Neyagawa 572, Japan c Department of Electrical Engineering, Miyazaki University, Miyazaki 889-21, Japan d R / D Engineering Department, Scientific Equipment Division, Shimadzu Co. Ltd., Kyoto 604, Japan Received 24 May 1990; accepted for publication 15 June 1990 The interaction of an intense laser beam in the VUV region with synthetically grown crystalline SiO2 as well as with synthetic amorphous SiO2 are extensively studied by X-ray photoelectron spectroscopy. The desorption of oxygen is induced by the bombardment of 9.8 eV photons produced from an Ar excimer laser, leaving behind elemental silicon in a surface layer of 50 nm depth. 8.5 eV photons produced from a krypton excimer laser do not induce such phenomena. The oxygen desorption and silicon precipitation are an intrinsic property of silicon dioxide. The reaction kinetics are also discussed.
Surface Science 242 (1991) 464-469 North-Holland
Thermal desorption of molecules coadsorbed on metal surfaces M. M i z u n o , H. Kasai and A. Okiji Department of Applied Physics, Osaka University, Suita, Osaka 565, Japan Received 16 May 1990; accepted for publication 13 June 1990 On the basis of the absolute reaction rate theory, the thermal desorption spectra of the coadsorption system, NO + C O / P t ( l l l ) , are calculated with the aid of the lattice gas model. It is shown that the spectra for NO molecules strongly depend on the coverage of preadsorbed CO molecules on a P t ( l l l ) surface. A good account of the experimental results is given for the thermal desorption spectra of NO molecules on a P t ( l l l ) surface with pre-adsorbed CO molecules.
470
Surface Science 242 (1991) 470-474
Molecule-surface complexes and catalytic reactions Ernest Ilisca 1 Research Center for Extreme Materials, Osaka University, Toyonaka, Osaka 560, Japan Received 18 May 1990; accepted for publication 11 June 1990 In physcial molecular adsorption and catalysis the building of surface-molecule complexes incl-des surface symmetries and opens therefore new intra-molecular catalytic channels. We illustrate this general property by investigating the o - p conversion of a hydrogen molecule adsorbed on a cold metal surface. A large family of processes is described with their relevant channels. Their common feature is the metal excitation of electron-hole triplet pairs with hyperfine contact at the H 2 protons. It is concluded that metallic conversion might be as efficient as the magnetic one displayed by insulators, even in the absence of molecular cliemisorption.
Surface Science 242 (1991) 475-480 North-Holland
475
Silicon precipitation in a surface layer of SiO 2 by high-power vacuum ultraviolet laser irradiation K o u K u r o s a w a a, Yasuo Takigawa b, Wataru Sasaki c, Masahiro Okuda a and Yoshihide Inoue d a Department of Electronics, Universityof Osaka Prefecture, Sakai 591, Japan b Department of Solid State Electronics, Osaka Electro-Communication University, Neyagawa 572, Japan c Department of Electrical Engineering, Miyazaki University, Miyazaki 889-21, Japan d R / D Engineering Department, Scientific Equipment Division, Shimadzu Co. Ltd., Kyoto 604, Japan Received 24 May 1990; accepted for publication 15 June 1990 The interaction of an intense laser beam in the VUV region with synthetically grown crystalline SiO2 as well as with synthetic amorphous SiO2 are extensively studied by X-ray photoelectron spectroscopy. The desorption of oxygen is induced by the bombardment of 9.8 eV photons produced from an Ar excimer laser, leaving behind elemental silicon in a surface layer of 50 nm depth. 8.5 eV photons produced from a krypton excimer laser do not induce such phenomena. The oxygen desorption and silicon precipitation are an intrinsic property of silicon dioxide. The reaction kinetics are also discussed.