Host Laboratory KIM LAB.
Position in LIMMS EUJO-LIMMS Researcher (EPFL)
Main Research Topic in LIMMS

Top-down contacting of single InAs quantum dots using AFM & SEM


Quantum dots, contacting, AFM, SEM


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 :


Research Projects in Limms

1- Top-down contacting of single InAs quantum dots using AFM & SEM 
Context :
InAs quantum dots are interesting for novel terahertz applications due to their energy level spacing [1]. this research is performed as an internship project of three months as part of master's program in applied physics. In this work a method to align electrodes made with electron beam lithography to 50-100nm wide InAs quantum dots with a contact yield of approximately 60% is demonstrated.
Objectives & Methods :
the goal is to deliver a reliable top-down method of contacting quantum dots for research purposes as currently the contacting of dots relies largely on luck [2]. Both SEM and AFM are employed. Quantum dot positions are determined relative to an existing bit marker structure, see figure 1, from which a mask is designed to deposit electrodes in a standard lithography process using both electron beam and photolithography.
Results :
A successful contact yield of approximately 60% is demonstrated, where the result using an AFM are superior to those using an SEM. An example of a successful contact is shown in figure 2.
References :
[1] P. M. Petroff, Phys. Today, Vol. 52, 2001.
[2] M. Jung. applied Physics Letters, Vol. 87, 2005.


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