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Research
Topics |
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■Research topics
(1) Formation of quantum nanostructure arrays and by metalorganic vapor
phase epitaxial growth
It is important to realize size- and site-controlled
array of compound semiconductor quantum nanostructures, namely, "Quantum
Crystals", in order for their application to quantum electronic
and optoelectronic devices, making full use of the superior electronic
and optical properties of compound semiconductors. The objective of this
research subject is to develop a technology for the realization of high-density
quantum nanostructure arrays using metalorganic vapor phase epitaxial
growth, which is a key technology to realize compound semiconductor devices
available on market. To now, we have succeeded in the formation of "quantum
dot network" structure (Fig.1), in which quantum wires and quantum
dots are arranged and coupled together in about 200nm periodicity, and
periodic triangular-lattice array of hexagonal pillars (Fig.2) which
can be used for photonic crystals.
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(2) Physics and device application of quantum nanostructure arrays
The objective of this subject is to understand
physics in high-density coupled array of quantum nanostructures, and their
electronic and photonic device applications via controlling both the quantum
state of electrons and photonic state of light. We have succeed in the
fabrication of quantum wire lasers (Fig. 3) realized by using high-density
array of quantum wires, single electron transistors and their integrated
circuits (Fig. 4). We also are trying to explore the electronic states
and single electron transport in single and coupled quantum dots by optical
and electronic study, as well as properties of photonic crystals.
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Fig3
Schematic Cross section of Quantum Wire Laser and (b) its output characteristics.
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Fig4
(a) SEM image of Single Electron Inverter formed by selective area MOVPE,
(b) equivalent circuit, (c) Coulomb Oscillation of single electron transistor,
and (d) I-O characteristics of single electron inverter.
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