X-ray source combined ultrahigh-vacuum scanning tunneling microscopy for elemental analysis

Author(s):  
Y. Hasegawa ◽  
K. Tsuji ◽  
K. Nakayama ◽  
K. Wagatsuma ◽  
T. Sakurai
Author(s):  
H.-J. Cantow ◽  
H. Hillebrecht ◽  
S. Magonov ◽  
H. W. Rotter ◽  
G. Thiele

From X-ray analysis, the conclusions are drawn from averaged molecular informations. Thus, limitations are caused when analyzing systems whose symmetry is reduced due to interatomic interactions. In contrast, scanning tunneling microscopy (STM) directly images atomic scale surface electron density distribution, with a resolution up to fractions of Angstrom units. The crucial point is the correlation between the electron density distribution and the localization of individual atoms, which is reasonable in many cases. Thus, the use of STM images for crystal structure determination may be permitted. We tried to apply RuCl3 - a layered material with semiconductive properties - for such STM studies. From the X-ray analysis it has been assumed that α-form of this compound crystallizes in the monoclinic space group C2/m (AICI3 type). The chlorine atoms form an almost undistorted cubic closed package while Ru occupies 2/3 of the octahedral holes in every second layer building up a plane hexagon net (graphite net). Idealizing the arrangement of the chlorines a hexagonal symmetry would be expected. X-ray structure determination of isotypic compounds e.g. IrBr3 leads only to averaged positions of the metal atoms as there exist extended stacking faults of the metal layers.


2001 ◽  
Vol 89 (1) ◽  
pp. 181-187 ◽  
Author(s):  
C. M. Schmidt ◽  
D. E. Bürgler ◽  
D. M. Schaller ◽  
F. Meisinger ◽  
H.-J. Güntherodt ◽  
...  

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2521
Author(s):  
Marshall van Zijll ◽  
Samantha S. Spangler ◽  
Andrew R. Kim ◽  
Hazel R. Betz ◽  
Shirley Chiang

Isolated pyramids, 30–80 nm wide and 3–20 nm tall, form during sputter-annealing cycles on the Ge (110) surface. Pyramids have four walls with {19 13 1} faceting and a steep mound at the apex. We used scanning tunneling microscopy (STM) under ultrahigh vacuum conditions to periodically image the surface at ion energies between 100 eV and 500 eV and incremental total flux. Pyramids are seen using Ar+ between 200 eV and 400 eV, and require Ag to be present on the sample or sample holder. We suspect that the pyramids are initiated by Ag co-sputtered onto the surface. Growth of pyramids is due to the gathering of step edges with (16 × 2) reconstruction around the pyramid base during layer-by-layer removal of the substrate, and conversion to {19 13 1} faceting. The absence of pyramids using Ar+ energies above 400 eV is likely due to surface damage that is insufficiently annealed.


1994 ◽  
Vol 50 (16) ◽  
pp. 12246-12249 ◽  
Author(s):  
J. C. Woicik ◽  
G. E. Franklin ◽  
Chien Liu ◽  
R. E. Martinez ◽  
I.-S. Hwong ◽  
...  

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