scholarly journals Layer-by-Layer Pyramid Formation from Low-Energy Ar+ Bombardment and Annealing of Ge (110)

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2521
Author(s):  
Marshall van Zijll ◽  
Samantha S. Spangler ◽  
Andrew R. Kim ◽  
Hazel R. Betz ◽  
Shirley Chiang
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Ultrahigh Vacuum ◽  
Surface Damage ◽  
Low Energy ◽  
Scanning Tunneling ◽  
Layer By Layer ◽  
Sample Holder ◽  
Tunneling Microscopy ◽  
Ion Energies ◽  
20 Nm

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.

scholarly journals Lateral ordering of PTCDA on the clean and the oxygen pre-covered Cu(100) surface investigated by scanning tunneling microscopy and low energy electron diffraction

2014 ◽  
Vol 10 ◽  
pp. 2055-2064 ◽  
Author(s):  
Stefan Gärtner ◽  
Benjamin Fiedler ◽  
Oliver Bauer ◽  
Antonela Marele ◽  
Moritz M Sokolowski
Keyword(s):  
Electron Diffraction ◽  
Scanning Tunneling Microscopy ◽  
Low Energy ◽  
Energy Electron ◽  
Scanning Tunneling ◽  
Structure Model ◽  
Tunneling Microscopy ◽  
Low Energy Electron Diffraction ◽  
Low Energy Electron ◽  
Lattice Planes

We have investigated the adsorption of perylene-3,4,9,10-tetracarboxylic acid dianhydride (PTCDA) on the clean and on the oxygen pre-covered Cu(100) surface [referred to as (√2 × 2√2)R45° – 2O/Cu(100)] by scanning tunneling microscopy (STM) and low energy electron diffraction (LEED). Our results confirm the (4√2 × 5√2)R45° superstructure of PTCDA/Cu(100) reported by A. Schmidt et al. [J. Phys. Chem. 1995, 99,11770–11779]. However, contrary to Schmidt et al., we have no indication for a dissociation of the PTCDA upon adsorption, and we propose a detailed structure model with two intact PTCDA molecules within the unit cell. Domains of high lateral order are obtained, if the deposition is performed at 400 K. For deposition at room temperature, a significant density of nucleation defects is found pointing to a strong interaction of PTCDA with Cu(100). Quite differently, after preadsorption of oxygen and formation of the (√2 × 2√2)R45° – 2O/Cu(100) superstructure on Cu(100), PTCDA forms an incommensurate monolayer with a structure that corresponds well to that of PTCDA bulk lattice planes.

Observation of Nanosized Cap Structures on 6H–SiC(000\bar1) Substrates by Ultrahigh-Vacuum Scanning Tunneling Microscopy

2006 ◽  
Vol 45 (1A) ◽  
pp. 372-374 ◽  
Author(s):  
Hyungjin Bang ◽  
Yuka Ito ◽  
Yasuyuki Kawamura ◽  
Etsuko Hosoda ◽  
Chisa Yoshida ◽  
...  
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Ultrahigh Vacuum ◽  
Scanning Tunneling ◽  
Tunneling Microscopy
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