Quantum Tunneling Microscope Lab Report

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Application of quantum electron tunneling
Scanning tunneling microscopy: Scanning tunneling microscope is a device used to map to topography of a material at atomic level. It works by running a sharp tip which is only a single atom thick over the surface of material. The tip voltage is higher than material. This voltage allows tunneling current to flow from electrons that tunnel from the surface of material to tip of material through potential barrier. By measuring the amount of current the microscope can resolve where the atoms are on the surface of the material.
[(Binnig, G., & Rohrer, H. (1983). Scanning tunneling microscopy. Surface science, 126(1-3), 236-244.)
(https://brilliant.org/wiki/quantum-tunneling/ )]
Josephan junctions:
Some semiconductor materials are superconductors, which means that in certain temperature ranges, a current can flow indefinitely without resistive heating
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Single electron tunneling is involved in precise measurements of two cryogenic capacitors. Single electron tunneling electrometer is used as a null detector for a capacitance bridge in these measurements. If the capacitance is very small the voltage buildup can be large enough to prevent another electron from tunneling. The resistance is than no longer constant because the electric current is suppressed at low bias voltages. Then resistance around zero bias is called coulomb blockade. Coulomb blockade causes reduce conduction below a critical bias voltage.
To observe coulomb blockade the temperature has to be low enough so that the characteristics changing energy is larger than the thermal energy of charge carries. A coulomb blockade can also be observed by making the device so small like quantum dot.
[( Clark, A. F., Zimmerman, N. M., Williams, E. R., Amar, A., Song, D., Wellstood, F. C & Soulen Jr, R. J. (1995). Application of single electron tunneling: Precision capacitance ratio measurements. Applied physics letters, 66(19),

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