UHV-STM studies of silicon nano-pyramid growth on silicon surface at high temperature

1992 ◽  
Vol 50 (2) ◽  
pp. 1144-1145
Author(s):  
T. Sato ◽  
S. Kitamura ◽  
T. Sueyoshl ◽  
M. Iwatukl ◽  
C. Nielsen
Keyword(s):  
High Temperature ◽  
Relaxation Process ◽  
Thermal Effect ◽  
Bias Voltage ◽  
Silicon Surface ◽  
Growth Process ◽  
Tunneling Current ◽  
Fabrication Technique ◽  
Nano Fabrication ◽  
Electromigration Effect

Recently, the growth process and relaxation process of crystalline structures were studied by observing a SI nano-pyramid which was built on a Si surface with a UHV-STM. A UHV-STM (JEOL JSTM-4000×V) was used for studying a heated specimen, and the specimen was kept at high temperature during observation. In this study, the nano-fabrication technique utilizing the electromigration effect between the STM tip and the specimen was applied. We observed Si atoms migrated towords the tip on a high temperature Si surface.Clean surfaces of Si(lll)7×7 and Si(001)2×l were prepared In the UHV-STM at a temperature of approximately 600 °C. A Si nano-pyramid was built on the Si surface at a tunneling current of l0nA and a specimen bias voltage of approximately 0V in both polarities. During the formation of the pyramid, Images could not be observed because the tip was stopped on the sample. After the formation was completed, the pyramid Image was observed with the same tip. After Imaging was started again, the relaxation process of the pyramid started due to thermal effect.

scholarly journals Fabrication of Nanowires Based on Polystyrene Derivatives by Single Particle Nano-Fabrication Technique

2012 ◽  
Vol 25 (5) ◽  
pp. 685-688
Author(s):  
Atsushi Asano ◽  
Yuta Maeyoshi ◽  
Katsuyoshi Takano ◽  
Masaaki Omichi ◽  
Masaki Sugimoto ◽  
...  
Keyword(s):  
Single Particle ◽  
Fabrication Technique ◽  
Nano Fabrication

Effect of Drilling Fluid Temperature on Formation Fracture Pressure Gradient

2021 ◽  
Author(s):  
Ahmed Mostafa Samak ◽  
Abdelalim Hashem Elsayed
Keyword(s):  
High Temperature ◽  
Pressure Gradient ◽  
Thermal Effect ◽  
Drilling Fluid ◽  
Wellbore Stability ◽  
Cooling Effect ◽  
Fluid Temperature ◽  
Lost Circulation ◽  
Fracture Pressure ◽  
Downhole Temperature

Abstract During drilling oil, gas, or geothermal wells, the temperature difference between the formation and the drilling fluid will cause a temperature change around the borehole, which will influence the wellbore stresses. This effect on the stresses tends to cause wellbore instability in high temperature formations, which may lead to some problems such as formation break down, loss of circulation, and untrue kick. In this research, a numerical model is presented to simulate downhole temperature changes during circulation then simulate its effect on fracture pressure gradient based on thermo-poro-elasticity theory. This paper also describes an incident occurred during drilling a well in Gulf of Suez and the observations made during this incident. It also gives an analysis of these observations which led to a reasonable explanation of the cause of this incident. This paper shows that the fracture pressure decreases as the temperature of wellbore decreases, and vice versa. The research results could help in determining the suitable drilling fluid density in high-temperature wells. It also could help in understanding loss and gain phenomena in HT wells which may happen due to thermal effect. The thermal effect should be taken into consideration while preparing wellbore stability studies and choosing mud weight of deep wells, HPHT wells, deep water wells, or wells with depleted zones at high depths because cooling effect reduces the wellbore stresses and effective FG. Understanding and controlling cooling effect could help in controlling the reduction in effective FG and so avoid lost circulation and additional unnecessary casing points.

scholarly journals Formation of 1-D Nano-materials by Single Particle Nano-fabrication Technique

Materia Japan ◽  
2014 ◽  
Vol 53 (11) ◽  
pp. 520-523
Author(s):  
Shu Seki ◽  
Satoshi Tsukuda ◽  
Shun-Ichiro Tanaka ◽  
Masaki Sugimoto
Keyword(s):  
Single Particle ◽  
Nano Materials ◽  
Fabrication Technique ◽  
Nano Fabrication

Electron Spin-Dependent Tunneling Current through a Trapezoidal Potential Barrier under Airy Wavefunction Approach

2020 ◽  
Vol 833 ◽  
pp. 152-156
Author(s):  
Fatimah A. Noor ◽  
Ezra Nabila ◽  
Euis Sustini ◽  
Khairurrijal
Keyword(s):  
Potential Barrier ◽  
Bias Voltage ◽  
Electron Spin ◽  
Tunneling Current ◽  
Spin States ◽  
Analytical Expression ◽  
Zinc Blende ◽  
Spin Polarized

In this paper, an analytical expression of the electron spin-dependent tunneling current through a potential barrier by applying a bias voltage was investigated. An Airy wavefunction was applied to derive the transmittance through the barrier by considering a zinc-blende material, which depends on the spin states indicated as ‘up’ and ‘down’. The obtained transmittance was employed to compute the polarization and spin-dependent tunneling current. The spin-dependent tunneling current was then observed at various bias voltages and temperatures. It was shown that the spin-polarized current increases as the bias voltage increases. It was also shown that the increase of temperature enhances the spin-dependent tunneling current.

Direct formation of sol-gel hybrid nanowires using single particle nano-fabrication technique

2011 ◽  
Vol 206 (5) ◽  
pp. 825-828 ◽  
Author(s):  
Satoshi Tsukuda ◽  
Shu Seki ◽  
Masaki Sugimoto ◽  
Akira Idesaki ◽  
Shun-Ichiro Tanaka
Keyword(s):  
Single Particle ◽  
Sol Gel ◽  
Fabrication Technique ◽  
Nano Fabrication ◽  
Direct Formation

scholarly journals The effect of STM parameters on tip-enhanced Raman spectra

2017 ◽  
Vol 205 ◽  
pp. 233-243 ◽  
Author(s):  
Natalia Martín Sabanés ◽  
Amala Elizabeth ◽  
Jonas H. K. Pfisterer ◽  
Katrin F. Domke
Keyword(s):  
Theoretical Model ◽  
Raman Spectra ◽  
Bias Voltage ◽  
Tunneling Current ◽  
Scanning Tunneling ◽  
Set Point ◽  
Point Increase ◽  
Distance Change

In this work, we evaluate the dependence of tip-enhanced Raman (TER) spectra of a monolayer of thiophenol at a Au(111) electrode on the scanning tunneling microscope’s tunneling current set-point and bias voltage parameters. We find an increase of the TER intensity upon set-point increase or bias decrease as expected from a gap-distance reduction. The relations obtained follow a theoretical model considering a simple gap-distance change when tuning the mentioned parameters. We find that the value of the bias voltage affects the TER intensity to a larger extent than the current set-point. Therefore it is advisable to work in a low-bias regime when aiming for ultrasensitive TER measurements.

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