Electronic sputtering of thin lithium fluoride films induced by swift heavy ions. (23rd July 2015)

• Record Type: Journal Article
• Authors: Martinez, R; Langlinay, Th; Boduch, P; Cassimi, A; Hijazi, H; Ropars, F; Salou, P; da Silveira, E F; Rothard, H
• Is Part Of: Materials research express. Volume 2:Number 7(2015)
• Publication Date: 2015-07-23
• Subjects: cluster formation and stability -- sputtering -- thin films -- lithium fluoride -- swift heavy ions -- highly charged ions; 34.50.Bw -- 36.40.Wa -- 79.20.Rf; Materials science -- Research -- Periodicals; Materials science -- Periodicals; 620.11
• DOI: 10.1088/2053-1591/2/7/076403
• Languages: English
• ISSNs: 2053-1591

Abstract

Abstract: The sputtering of secondary ions from thin lithium fluoride films of different thickness (2 nm ≤ z ≤ 106 nm) irradiated by swift heavy ions (Ni and Ge: ∼10 MeV/ u ) was studied under ultrahigh-vacuum conditions by a time-of-flight imaging technique ( XY -TOF-SIMS). Most of the positive ions emitted are (LiF) n Li + clusters. Cluster structure and stability (magic numbers) are analyzed. A pronounced dependence of sputtered particle yields on the film thickness z was observed. The onset of large cluster emission occurs at a thickness of about z = 20 nm. For thinner films, z = 2 and z = 4 nm, only small clusters ( n < 6) are ejected. A threshold for the emission of large clusters was also observed as a function of the electronic stopping power S e at around 6 keV nm −1 . This leads to the important conclusion that both a sufficient amount of material ( z -dependence) and of deposited energy ( S e -dependence) are needed for large ionic cluster emission to occur.