Electronic and Vibrational Properties of Single Crystal Surfaces of NiAl

1986 ◽  
Vol 83 ◽  
Author(s):  
S.-C. Lui ◽  
J. M. Mundenar ◽  
E. W. Plummer ◽  
M. E. Mostoller ◽  
R. M. Nicklow ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Nearest Neighbor ◽  
Surface States ◽  
Active Surface ◽  
Atomic Displacement ◽  
Inelastic Electron ◽  
Crystal Surfaces ◽  
Single Crystal Surfaces ◽  
Nial Alloy ◽  
Bulk Surface

ABSTRACTSurface and bulk electronic structure of the ordered NiAl alloy were measured using angle resolved photoelectron spectroscopy. The measured bulk d-bands (Ni like) were observed to be narrower than theoretically calculated d band widths which are 20 to 40% wider (depending upon what is used as a measure of the width). At least two surface states were observed on both the (110) and (111) surfaces. The nature of these surface states and their relationship to the bulk band structure is discussed. Dispersion of bulk phonons was measured by neutron scattering and fitted with a fourth nearest neighbor Born-von Karman model. Dipole active surface phonons on the (110) and (111) surfaces were observed by inelastic electron scattering and the frequencies also calculated assuming a truncated bulk surface. The calculated surface modes present a qualitative picture of the atomic displacement at each surface and also show that the surface phonon energy and intensity depends upon the structure of the surface.

Copper CVD Reactions of Cu(I)(hfae)(vtms) Adsorbed on TiN

1992 ◽  
Vol 282 ◽  
Author(s):  
K. V. Guinn ◽  
V. M. Donnelly ◽  
M. E. Gross ◽  
F. A. Baiocchi ◽  
I. Petrov ◽  
...  
Keyword(s):  
Single Crystal ◽  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Ion Beam ◽  
Surface Preparation ◽  
Crystal Surfaces ◽  
Single Crystal Surfaces ◽  
X Ray ◽  
Gaseous Products ◽  
Mocvd Precursor

ABSTRACTWe have studied the thermal decomposition of a Cu MOCVD precursor, hexafluoroacetylacetonate copper vinyl trim ethylsilane (CuI (hfac)(vtms)), on both air-oxidized and N2 ion beam sputter-annealed single crystal (100) and polycrystalline TiN surfaces. Dosing TiN with CuI(hfac)(vtms) at 25°C results in chemisorption of CuIhfac) and desorption of vtms. On oxidized surfaces, litle or no decomposition of CF3 groups is detected at room temperature, while on sputter-annealed polycrystalline and single crystal surfaces, a small amount of decomposition is indicated by a CF2 feature in the C(1s) X-ray photoelectron spectroscopy (XPS) spectrum, and a low-binding energy fluoride in the F(1s) spectrum. Between 100 and 250°C, CuI(hfac) decomposes to evolve gaseous products and leaves Cu, F, and C on the surface. Further heating leads to diffusion of Cu into the TiN, apparently enhanced by simultaneous diffusion of F. Decomposition of the hfac CF3 groups at elevated temperature is independent of the nature of the TiN surface (i.e. polycrystalline vs. (100), or clean vs. oxidized). However, Cu diffusion depends strongly on the surface preparation. The onset of Cu diffusion into oxidized polycrystalline, clean polycrystalline, and clean single crystal (100) TiN occurs at 250, 320, and 430°C, respectively.

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