University of Twente Student Theses


Electron interferometer investigation for coherent electron transport in organic modules

Shawrav, Mostafa Moonir (2010) Electron interferometer investigation for coherent electron transport in organic modules.

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Abstract:This project aims to investigate the degree of coherence of electron transport through organic molecules. An Aharonov-Bohm ring has chosen as a probe for coherence transport of the electrons. Three different structures namely hexagonal AB ring, junction with space and line with gap have designed to observe AB oscillation, increase the resistance of the junction and insert the nanoparticles in different gaps respectively. Electron-beam lithography has used to write the structure as the device dimension is far below the diffractio limit of light. A new sample holder has designed where the voltage probe and current supply are in the same twisted pair. The same holder is also mounted at the cold finger. All the wirings of the new sample holder has completed successfully. Aharonov-Bohm oscillations with reproducible AB period have been observed with the help of sensitive measurement electronics and a cryiogenic setup. Subsequently further investigation on the effect of geometry, temperature and the excitation current to the AB oscillation was done. Measured AB period of the oscillation is in agreement with the theoretical value for rings with different dimensions. Also a superconducting behavior due to the contact pads had observerd. In future, nanoparticale bridging techniques can be used to insert monolayer of molecules into the Aharonov-Bohm ring to investigate the effect of the molecule to the coherency.
Item Type:Essay (Master)
Faculty:TNW: Science and Technology
Subject:33 physics
Programme:Nanotechnology MSc (60028)
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