scholarly journals Consistent probe spacing in multi-probe STM experiments

AIP Advances ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 105213
Author(s):  
Jo Onoda ◽  
Doug Vick ◽  
Mark Salomons ◽  
Robert Wolkow ◽  
Jason Pitters
Keyword(s):  
Probe Spacing

ELECTRICAL CONDUCTION THROUGH SURFACE SUPERSTRUCTURES MEASURED BY MICROSCOPIC FOUR-POINT PROBES

2003 ◽  
Vol 10 (06) ◽  
pp. 963-980 ◽  
Author(s):  
SHUJI HASEGAWA ◽  
ICHIRO SHIRAKI ◽  
FUHITO TANABE ◽  
REI HOBARA ◽  
TAIZO KANAGAWA ◽  
...  
Keyword(s):  
Scanning Tunneling Microscope ◽  
Scanning Tunneling ◽  
Conductivity Measurements ◽  
Crystal Surfaces ◽  
Tunneling Microscope ◽  
Silicon Chips ◽  
Surface Sensitivity ◽  
Scanning Electron ◽  
Probe Spacing

For in-situ measurements of the local electrical conductivity of well-defined crystal surfaces in ultrahigh vacuum, we have developed two kinds of microscopic four-point probe methods. One involves a "four-tip STM prober," in which four independently driven tips of a scanning tunneling microscope (STM) are used for measurements of four-point probe conductivity. The probe spacing can be changed from 500 nm to 1 mm. The other method involves monolithic micro-four-point probes, fabricated on silicon chips, whose probe spacing is fixed around several μm. These probes are installed in scanning-electron-microscopy/electron-diffraction chambers, in which the structures of sample surfaces and probe positions are observed in situ. The probes can be positioned precisely on aimed areas on the sample with the aid of piezoactuators. By the use of these machines, the surface sensitivity in conductivity measurements has been greatly enhanced compared with the macroscopic four-point probe method. Then the conduction through the topmost atomic layers (surface-state conductivity) and the influence of atomic steps on conductivity can be directly measured.

An in situ probe-spacing-correction thermo-TDR sensor to measure soil water content accurately

2018 ◽  
Vol 69 (6) ◽  
pp. 1030-1034 ◽  
Author(s):  
M. M. Wen ◽  
G. Liu ◽  
R. Horton ◽  
K. Noborio
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Probe Spacing

Time-of-flight diffraction method for joint with linear misalignment

2021 ◽  
Vol 63 (11) ◽  
pp. 654-658
Author(s):  
Y Kurokawa ◽  
T Kawaguchi ◽  
H Inoue
Keyword(s):  
Exact Solution ◽  
Approximate Solution ◽  
Geometric Model ◽  
Time Of Flight ◽  
Diffraction Method ◽  
Approximate Solutions ◽  
Weld Joints ◽  
Time Of Flight Diffraction ◽  
Flaw Sizing ◽  
Probe Spacing

The time-of-flight diffraction (TOFD) method is known as one of the most accurate flaw sizing methods among the various ultrasonic testing techniques. However, the standard TOFD method cannot be applied to weld joints with linear misalignment because of its basic assumptions. In this study, a geometric model of the TOFD method for weld joints with linear misalignment is introduced and an exact solution for calculating the flaw tip depth is derived. Since the exact solution is extremely complex, a simple approximate solution is also derived assuming that the misalignment is sufficiently small relative to the probe spacing and the flaw tip depth. The error in the approximate solution is confirmed to be negligible if the assumptions are satisfied. Numerical simulations are conducted to assess the flaw sizing accuracy of both the exact and approximate solutions considering the constraint of the probe spacing and the influence of the excess metal shape. Finally, experiments are conducted to prove the applicability of the proposed method. As a result, the proposed method is proven to enable accurate flaw sizing of weld joints with linear misalignment.

Probe Reversal and Pressure Based Bias Error Correction Procedures Applied to Intensity Measurements in Planar Standing Waves

1995 ◽  
Vol 117 (1) ◽  
pp. 56-61
Author(s):  
R. W. Guy ◽  
H. Luchian
Keyword(s):  
Standing Wave ◽  
Standing Waves ◽  
Low Frequency ◽  
Superior Performance ◽  
Bias Error ◽  
Low Frequencies ◽  
Pressure Correction ◽  
Phase Errors ◽  
Intensity Measurements ◽  
Probe Spacing

An analytical application of probe reversal and pressure correction strategies to minimize channel phase errors in P-P intensity measurements within discrete frequency standing waves is made. Two potential error sources, error of position upon reversal and error of pressure correction, are examined and found negligible at low frequencies but likely to be problematic at high frequencies. It is predicted that pressure correction or probe reversal can lead to superior performance when compared with measures without correction at modest and higher standing wave ratios in true intensity assessment; the frequency range for a given probe spacing is also extended. The correction procedures are then applied to low frequency measurements (63 Hz and 125 Hz) for a range of standing wave ratios. It is found that correction procedures generally lead to better results than uncorrected measures, but beyond a standing wave ratio of about 30 dB at 63 Hz additional error source arises which renders inaccurate the result of correction procedures, particularly for smaller probe spacing measures.

Precision Over‐Under Four‐Point Probe with a Small Probe Spacing

1964 ◽  
Vol 35 (8) ◽  
pp. 959-962 ◽  
Author(s):  
P. A. Schumann ◽  
L. S. Sheiner
Keyword(s):  
Small Probe ◽  
Probe Spacing
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