Ripening Mechanisms in Ultrathin Metal Films

1998 ◽  
Vol 528 ◽  
Author(s):  
Georg Rosenfeld ◽  
Marcus Essera ◽  
Karina Morgensternat ◽  
George Comsa
Keyword(s):  
Ostwald Ripening ◽  
Mean Field ◽  
Metal Films ◽  
Binary Collision ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Island Size ◽  
Model Studies ◽  
Ultrathin Metal Films ◽  
Local Correlations

AbstractResults of recent experimental model studies on ripening of submonolayer films via Ostwald ripening and dynamic coalescence are described. The experiments have been performed on ensembles of Ag-adatom or vacancy islands on a Ag(111) surface using Scanning Tunneling Microscopy. For Ostwald ripening of adatom islands, deviations from the classical mean-field ripening behaviour are observed which show up as pronounced local correlations in island decay and growth rates. For ripening via dynamic coalescence which is studied for ensembles of vacancy islands, it is found that the increase of the average island size with time in the late-stage regime is correctly described by the classical binary collision model.

Island Size and Environment Dependence of Adatom Capture: Cu/Co Islands on Ru(0001)

1998 ◽  
Vol 528 ◽  
Author(s):  
M.C. Bartelt ◽  
J.W. Evans ◽  
A.K. Schmid ◽  
R.Q. Hwang
Keyword(s):  
Kinetic Monte Carlo ◽  
Strong Dependence ◽  
Mean Field ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Island Size ◽  
Kinetic Monte Carlo Simulations ◽  
Environment Dependence ◽  
And Diffusion ◽  
Capture Rates

AbstractThe rate of capture by stable Co islands on Ru(0001) of additionally deposited Cu atoms is quantified using scanning tunneling microscopy, kinetic Monte Carlo simulations, and diffusion equation analyses. We find strong dependence of the capture rates on Co-island size, larger islands showing larger capture rates, qualitatively distinct from self-consistent mean-field predictions. The observed size dependence is shown to reflect larger island-free areas surrounding bigger islands, i.e., a strong correlation between island sizes and separations neglected in mean-field treatments.

IN-SITU HIGH-TEMPERATURE SCANNING-TUNNELING-MICROSCOPY STUDIES OF TWO-DIMENSIONAL ISLAND-DECAY KINETICS ON ATOMICALLY SMOOTH TiN(001)

2000 ◽  
Vol 07 (05n06) ◽  
pp. 589-593 ◽  
Author(s):  
S. KODAMBAKA ◽  
V. PETROVA ◽  
A. VAILIONIS ◽  
P. DESJARDINS ◽  
D. G. CAHILL ◽  
...  
Keyword(s):  
High Temperature ◽  
Scanning Tunneling Microscopy ◽  
Ostwald Ripening ◽  
Single Atom ◽  
Scanning Tunneling ◽  
Two Dimensional ◽  
Decay Kinetics ◽  
Tunneling Microscopy ◽  
Temperature Scanning

In-situ high-temperature scanning tunneling microscopy was used to follow the coarsening (Ostwald ripening) and decay kinetics of single and multiple two-dimensional TiN islands on atomically flat TiN (001) terraces and in single-atom deep vacancy pits at temperatures of 750–950°C. The rate-limiting mechanism for island decay was found to be surface diffusion rather than adatom attachment/detachment at island edges. We have modeled island-decay kinetics based upon the Gibbs–Thomson and steady state diffusion equations to obtain a step-edge energy per unit length of 0.23±0.05 eV/Å and an activation energy for adatom formation and diffusion of 3.4±0.3 eV.

Island decay on the anisotropic Ag(110) surface

2000 ◽  
Vol 648 ◽  
Author(s):  
Karina Morgenstern ◽  
Erik Lægsgaard ◽  
Flemming Besenbacher
Keyword(s):  
Decay Mode ◽  
Ostwald Ripening ◽  
Variable Temperature ◽  
Scanning Tunneling ◽  
Two Dimensional ◽  
Tunneling Microscopy ◽  
Sharp Transition ◽  
One Dimensional ◽  
Temperature Scanning ◽  
Rate Limiting

AbstractWe have investigated the decay of two-dimensional islands on the anisotropic Ag(110) surface using variable-temperature scanning tunneling microscopy. Contrary to predictions from traditional Ostwald ripening theory, a quasi-one-dimensional decay mode is observed at low temperatures (175-220 K). A surprisingly sharp transition to the quasi-two-dimensional decay mode is observed around 220 K. This transition is accompanied by a fast equilibration of the island shape. These findings have tentatively been rationalized within a simple model to identify the underlying rate limiting atomistic processes.

Characterization of Dislocation Reactivity and Dynamics in Thin Metal Films Using Scanning Tunneling Microscopy

2000 ◽  
Vol 6 (S2) ◽  
pp. 702-703
Author(s):  
R.Q. Hwang
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Chemical Properties ◽  
Metal Films ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Cu Film ◽  
External Forces ◽  
Complex Phenomena ◽  
Stm Images

The accommodation of strain in metal films can lead to complex phenomena, both structurally and chemically. It can generically lead to the formation of dislocations. These dislocations play an important role in defining the evolution and response of the film to further growth and external forces. The structures of the dislocations are directly analogous to bulk dislocations, but their properties are very different due to the presence of the surface. In addition, the strain can greatly affect the chemical properties of the film, leading to alternative strain relief mechanisms involving vacancy formation resulting from reaction with gases such as sulfur and oxygen. Using STM and LEEM, we have investigated these phenomena in the prototype systems of Cu and Ag on Ru(0001).For example, figure la - d shows a sequence of STM images of a 2 layer Cu film on Ru(0001) during exposure to oxygen. Dislocations present in the film are altered by reaction with oxygen.

Deposited metal films for imaging in scanning tunneling microscopy

1991 ◽  
Vol 243 (1-3) ◽  
pp. 179-192 ◽  
Author(s):  
Ursula Mazur ◽  
Glenn Fried ◽  
K.W Hipps
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Metal Films ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Deposited Metal

Probing large area surface plasmon interference in thin metal films using photon scanning tunneling microscopy

2004 ◽  
Vol 100 (3-4) ◽  
pp. 429-436 ◽  
Author(s):  
A. Passian ◽  
A. Wig ◽  
A.L. Lereu ◽  
P.G. Evans ◽  
F. Meriaudeau ◽  
...  
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Surface Plasmon ◽  
Metal Films ◽  
Thin Metal ◽  
Scanning Tunneling ◽  
Thin Metal Films ◽  
Large Area ◽  
Tunneling Microscopy

The Growth of Amorphous CuxTi1-x Films: Relationship Between Intrinsic Stresses and Microstructure Observed by STM

1994 ◽  
Vol 356 ◽  
Author(s):  
U. Von Hülsen ◽  
U. Geyer ◽  
S. Dina ◽  
G. von Minnigerode
Keyword(s):  
Surface Topography ◽  
Film Growth ◽  
Critical Value ◽  
Metal Films ◽  
Scanning Tunneling ◽  
Growth Stages ◽  
Tunneling Microscopy ◽  
Tensile Stresses ◽  
Compressive Stresses ◽  
Ti Films

AbstractThe evolution of the surface topography of thin amorphous Cu-Ti films during the film growth is investigated by scanning tunneling microscopy. The films begin to grow with smooth surfaces until the film thickness reaches a critical value. Then, within a small thickness interval, a grainy microstructure of the film develops which looks very similar to the microstructure of polycrystalline films. Measurements of the intrinsic macroscopic stress in these films during the film growth show compressive stresses in the early growth stages. Then a change to tensile stresses accompanies the change in the surface topography within the same thickness interval. Both, the surface topography and the intrinsic stresses, are always correlated and depend on the deposition temperature and on the film composition. We discuss implications of these observations on the origin of macroscopic intrinsic tensile stresses in amorphous transition metal films.

Sign in / Sign up

Export Citation Format

Share Document