Host Laboratory KAWAKATSU LAB.
Position in LIMMS EUJO-LIMMS Researcher (MESA+)
Main Research Topic in LIMMS NANOTECH - Terahertz photon assisted tunneling in InAs quantum dots

Terahertz, photon-assisted tunneling, single-electron transitor


Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan 
Phone:+81 (0)3 5452 6036 / Fax:+81 (0)3 5452 6088



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Short resume :
2012-now Actual position
2008-2012 Here
2004-2008 Here
2001-2003 Here

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Research Projects in Limms

1- FTerahertz photon assisted tunneling in InAs quantum dots 
Context :
Terahertz (THz) waves can be a powerful tool to investigate the electronic properties of nanostructure, since many of these structures have electronic excitation energy which correspond to the THz wavelength. Nanostructures such as quantum dots have generated much interest for their potential important roles in electronic devices such as quits and single-electron transistors. Indium arsenide (InAs) quantum dots (QDs) exhibit some unique characteristics which make it a great candidate for research purposes. In this work, it was tried to fabricate a device to measure these characteristics.
Objectives & Methods :
The objective of this project is to measure photon assisted tunneling (PAT) in InAs QDs. For this, QDs need to be connected to electrodes. These electrodes are shaped in a bow tie antenna, to enhance the field strength of the THz waves. To separate a single nanojunction into two electrodes, electromigration is used to break the junction. The nano junction can be seen in Fig.1. 
Results :
Though the nano junctions were fabricated successfully, the electromigration process seemed to continuously fail. As the conduction seemed to go to zero, indicating breaking of the junction, the conductance then seemed to increase rapidly and would not decrease afterwards, as can be seen in Fig.2. An explanation of this behavior was not found.
References :
[1] Shibata,K., et al., Phys. Rev. Lett., 109(7), 077401, 2012.

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Main publication List (papers, conferences and patent) 








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