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Field-ion microscopy and atom-probe mass spectroscopy of sulfur on the (111) plane of nickel
A448 Surface Science 147 (1984) 349 355 North-Holland, Amsterdam
349
FIELD-ION MICROSCOPY A N D A T O M - P R O B E M A S S S P E C T R O S C O P Y OF S U L F U R ON THE (111) PLANE OF NICKEL * J. H R E N ** and G.L. K E L L O G G *** Sandia National Laboratories, Albuquerque, New Mexico 87185, USA Received 18 April 1984; accepted for publication 2 August 1984 The adsorption of sulfur on nickel field emitter surfaces has been studied by field-ion microscopy and atom-probe mass spectroscopy. The sulfur was deposited by dosing the nickel surface with H2S gas at elevated temperatures ( ~ 500 K). Individual sulfur atoms on the close-packed (111) plane were found to image very clearly in the field-ion microscope, but were highly resistant to field desorption. Typically, 30 to 60 nickel (111) layers could be field evaporated before the sulfur was removed. Imaging atom-probe mass spectra taken from the (111) region contained sulfur signals only ocassionally, and these usually occurred upon the final collapse of a (111) plane. The results indicate that field-ion microscope studies of the structure of adsorbed sulfur overlayers on nickel are possible, but that atom-probe analysis of sulfur on nickel at temperatures above 40 K cannot be undertaken quantitatively.
356
Surface Science 147 (1984) 356-360 North-Holland, Ainsterdam
OBSERVATION OF S T R U C T U R A L CHANGE IN ORGANIC M O N O L A Y E R FILM BY PENNING IONIZATION ELECTRON SPECTROSCOPY: Fe-PHTHALOCYANINE ON GRAPHITE Yoshiya H A R A D A , Hiroyuki O Z A K I and Koichi O H N O Department of Chemistry. College of Arts and Scien~e.~. The Unil,ersttv of Tokyo, Meguro, Kornaha, Tokyo 153, Japan
and Takashi K A J I W A R A Department of Chemistry, l~culo ' of Science, Toho Uni~,ersitv, Mivama, Funaba~hi 274. Japan Received 3 July 1984 Structures of Fe-phthalocyanine adsorbed on a graphite substrate (cleavage plane) were studied by Penning ionization electron spectroscopy (PIES). The structural change, disordered layer closely packed monolayer -~ island, was observed upon heating the film deposited on the substrate held at 123 K. For the monolayer and island structures, molecules were found to be oriented fiat to the substrate. It was concluded that PIES was a useful technique to probe the change in molecular arrangement during order-disorder transformation in monolayer films.
349
FIELD-ION MICROSCOPY A N D A T O M - P R O B E M A S S S P E C T R O S C O P Y OF S U L F U R ON THE (111) PLANE OF NICKEL * J. H R E N ** and G.L. K E L L O G G *** Sandia National Laboratories, Albuquerque, New Mexico 87185, USA Received 18 April 1984; accepted for publication 2 August 1984 The adsorption of sulfur on nickel field emitter surfaces has been studied by field-ion microscopy and atom-probe mass spectroscopy. The sulfur was deposited by dosing the nickel surface with H2S gas at elevated temperatures ( ~ 500 K). Individual sulfur atoms on the close-packed (111) plane were found to image very clearly in the field-ion microscope, but were highly resistant to field desorption. Typically, 30 to 60 nickel (111) layers could be field evaporated before the sulfur was removed. Imaging atom-probe mass spectra taken from the (111) region contained sulfur signals only ocassionally, and these usually occurred upon the final collapse of a (111) plane. The results indicate that field-ion microscope studies of the structure of adsorbed sulfur overlayers on nickel are possible, but that atom-probe analysis of sulfur on nickel at temperatures above 40 K cannot be undertaken quantitatively.
356
Surface Science 147 (1984) 356-360 North-Holland, Ainsterdam
OBSERVATION OF S T R U C T U R A L CHANGE IN ORGANIC M O N O L A Y E R FILM BY PENNING IONIZATION ELECTRON SPECTROSCOPY: Fe-PHTHALOCYANINE ON GRAPHITE Yoshiya H A R A D A , Hiroyuki O Z A K I and Koichi O H N O Department of Chemistry. College of Arts and Scien~e.~. The Unil,ersttv of Tokyo, Meguro, Kornaha, Tokyo 153, Japan
and Takashi K A J I W A R A Department of Chemistry, l~culo ' of Science, Toho Uni~,ersitv, Mivama, Funaba~hi 274. Japan Received 3 July 1984 Structures of Fe-phthalocyanine adsorbed on a graphite substrate (cleavage plane) were studied by Penning ionization electron spectroscopy (PIES). The structural change, disordered layer closely packed monolayer -~ island, was observed upon heating the film deposited on the substrate held at 123 K. For the monolayer and island structures, molecules were found to be oriented fiat to the substrate. It was concluded that PIES was a useful technique to probe the change in molecular arrangement during order-disorder transformation in monolayer films.