The surface topography of pyrolitic carbons and of gold thin films by scanning tunneling microscopy: Grain boundaries and surface defects

1987 ◽  
Vol 154 (1-2) ◽  
pp. 65-73 ◽  
Author(s):  
B. Marchon ◽  
S. Ferrer ◽  
D.S. Kaufman ◽  
M. Salmeron ◽  
W. Siekhaus
Keyword(s):  
Thin Films ◽  
Scanning Tunneling Microscopy ◽  
Grain Boundaries ◽  
Surface Topography ◽  
Surface Defects ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Gold Thin Films

A scanning tunneling microscopy and potentiometry study of epitaxial thin films of La0.7Ca0.3MnO3

2002 ◽  
Vol 738 ◽  
Author(s):  
Mandar Paranjape ◽  
K. Shantha Shankar ◽  
A.K. Raychaudhuri ◽  
N.D. Mathur ◽  
M.G. Blamire
Keyword(s):  
Thin Films ◽  
Scanning Tunneling Microscopy ◽  
Grain Boundaries ◽  
Lattice Mismatch ◽  
Local Potential ◽  
Growth Unit ◽  
Scanning Tunneling ◽  
Epitaxial Thin Films ◽  
Tunneling Microscopy

ABSTRACTTo investigate the role of grain boundaries and other growth related microstructure in manganite films, a scanning tunneling microscope is used to simultaneously probe surface topography and local potential distribution under current flow at nanometer level in films of epitaxial thin films of La0.7Ca0.3MnO3deposited on single crystal SrTiO3and NdGaO3substrate by laser ablation. We have studied two types of films strained and strain relaxed. Thin (50nm) films (strained due to lattice mismatch between substrate and the film) show step growth (unit cell steps) and have very smooth surfaces. Relatively thicker films (strain relaxed, thickness 200nm) do not have these step growths and show rather smooth well connected grains. Charge transport in these films is not uniform on the nanometer level and is accompanied by potential jumps at the internal surfaces. In particular scattering from grain boundaries results in large variations in the local potential resulting in fields as high as 104-105V/cm located near the grain boundaries. We discuss the role of local strain and strain inhomogeneties in determining the current transport in these films and their resistance and magnetoresistivity. In this paper we attempt to correlate between bulk electronic properties with microscopic electronic conduction using scanning tunneling microscopy and scanning tunneling potentiometry.

Scanning Tunneling Microscopy and Atomic Force Microscopy Investigation of Organic Tetracyanoquinodimethane Thin Films

1997 ◽  
Vol 12 (8) ◽  
pp. 1942-1945 ◽  
Author(s):  
H. J. Gao ◽  
H. X. Zhang ◽  
Z. Q. Xue ◽  
S. J. Pang
Keyword(s):  
Thin Films ◽  
Atomic Force Microscopy ◽  
Scanning Tunneling Microscopy ◽  
Pyrolytic Graphite ◽  
Film Surface ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
Atomic Force ◽  
Microscopy Investigation

Scanning tunneling microscopy (STM) and atomic force microscopy (AFM) investigation of tetracyanoquinodimethane (TCNQ) and the related C60-TCNQ thin films is presented. Periodic molecular chains of the TCNQ on highly oriented pyrolytic graphite (HOPG) substrates were imaged, which demonstrated that the crystalline (001) plane was parallel to the substrate. For the C60-TCNQ thin films, we found that there were grains on the film surface. STM images within the grain revealed that the well-ordered rows and terraces, and the parallel rows in different grains were generally not in the same orientation. Moreover, the grain boundary was also observed. In addition, AFM was employed to modify the organic TCNQ film surface for the application of this type of materials to information recording and storage at the nanometer scale. The nanometer holes were successfully created on the TCNQ thin film by the AFM.

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