Energy-dependent deposition processes of size-selected Ag nanoclusters on highly-oriented pyrolytic graphite

Abstract

Singly charged cations of silver atoms and clusters ͑Ag n ϩ , nϭ1, 3,5,7,9) were deposited on highly oriented pyrolytic graphite substrates at well-controlled, various collision energies. The total amount of Ag atoms remaining on the substrates after collision was quantified by measuring the Ag 3d 5/2 photoelectron intensities. The collision energy dependence of the amount of deposited Ag atoms revealed that, for all the species, there are three distinct energy regions, for which soft landing, rebounding, or implantation is a dominant process, and that the energy ranges for the processes strongly depend on the cluster size. The deposition efficiency vs collision energy curve for each cluster is well fitted to that for Ag 1 , by considering the difference between the contact area of Ag 1 with the surface and that of the cluster, reflecting the compactness of the clusters. Boundaries between the different deposition regimes for the clusters were less distinct than those for Ag 1 . Considering anisotropy in shape of a cluster, deposition efficiency around the implantation threshold was calculated, which well explains the indistinctness of the threshold observed in the experimental data. This supports the picture that the energy given to a unit surface area determines the collision process.

Fabrication and Physical Properties of Mono- and Multilayer Metallic Nanostructures

“…В ряді робіт [71][72][73] було показано, що при енергіях нанесен-ня, які перевищують питому порогову енергію, нанокластери руйнують поверхневі зв'язки та проникають в поверхню або за-кріплюються на дефектах, які створюються самими кластерами [74]. У роботі [75] йдеться про дослідження та безпосереднє спо-стереження металевих нанокластерів ніклю на твердій поверхні монокристалу кремнію, напорошених з допомогою методи йонно-го розпорошення за кімнатної температури.…”

“…Ni 1 , Ni 3 і Ni 9 наносили на поверхню Si(111) 77 при дуже малих енергіях падіння, мен-ше 0,3 еВ/кластер для уникнення фраґментації. Експеримента-льну установку для ґенерації й осадження нанокластерів деталь-но описано в роботі [73]. Нанокластери Ni наносилися методою високоенергетичного йонного травлення.…”

Techniques for Fabricating Nanoscale Catalytic Circuits

“…Atom and particle deposition on flat surfaces in vacuo has been practiced for many years using continuous and pulsed sources, including Knudsen cells, and laser ablation systems [6][7][8][9][10][11][12][13][14][18][19][20][21][22]. Deposition on particles is often performed via chemical vapor deposition (CVD) in a fluid bed [23,24].…”

“…may occur on a single complex site, which performs the complete reaction, or on a number of different sites. Recent developments in the synthesis of nanoparticles [1][2][3], the preparation of monolayer catalysts [4], and in the development of atomic deposition techniques [5][6][7][8][9] present new opportunities to fabricate catalysts with different active sites capable of catalyzing different chemical reactions. Nanoscale catalytic units, such as metal clusters, or transition metal oxide nanoparticles can be prepared separately, and in principle, organized at the nanoscale level to perform a complex reaction sequence.…”

“…The deposition of atomic and molecular films, and the fabrication of nanoscale structures on flat surfaces such as silicon wafers, or other single crystal surfaces has been discussed in the literature [6][7][8][9][10][11][12][13][14]. We, recently, reported a method of directly depositing transition metal atoms on micron-sized quartz particles [5].…”