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Chemical implantation, isotopic trapping effects, and induced hygroscopicity resulting from 15 keV ion bombardment of sapphire

Journal Article · · J. Chem. Phys.; (United States)
DOI:https://doi.org/10.1063/1.432776· OSTI ID:7280108

Targets of single crystal sapphire (..cap alpha..-Al/sub 2/O/sub 3/) have been bombarded with 15 keV H/sup +/, D/sup +/, He/sup +/, Ne/sup +/, and Ar/sup +/. The H/sup +/ and D/sup +/ chemically implant, as indicated by the production of ir absorption bands at 3400 and 2450 cm/sup -1/, attributed to the hydroxyl and deuteroxyl stretching frequencies, respectively. At ion fluences of 1 x 10/sup 17/ cm/sup -2/ the chemical trapping efficiency of D/sup +/ as calculated from the integrated deuteroxyl band intensity is of the order of unity. The number of D/sup +/ chemically trapped as deuteroxyl saturates at about 2 x 10/sup 17/ cm/sup -2/ of target surface area, and at higher D/sup +/ fluences physical trapping of deuterium in gas blisters becomes the dominant trapping mechanism. By contrast, chemical trapping of H/sup +/ saturates at about 7 x 10/sup 16/ cm/sup -2/. This isotopic effect can be rationalized in terms of the greater displacement damage resulting from D/sup +/ bombardment. The surfaces of sapphire targets subjected to 15 keV H/sup +/, D/sup +/, and He/sup +/ bombardments at fluences above 2 x 10/sup 17/ cm/sup -2/ exhibit an induced hygroscopicity characterized by a growing hydroxyl band absorption on exposure to water vapor. Blisters indicative of physical trapping are observed for H/sup +/ and He/sup +/ as well as for high fluence D/sup +/ bombardments. There is no evidence of blistering or induced hygroscopicity due to Ne/sup +/ or Ar/sup +/ bombardments. The results for H/sup +/ and D/sup +/ are extrapolated to T/sup +/ and the implications for chemical sputtering are considered. (AIP)

Research Organization:
Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439
OSTI ID:
7280108
Journal Information:
J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 65:1; ISSN JCPSA
Country of Publication:
United States
Language:
English