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Architectural Photonics: A New Concept for Enhancing Opto-electronic Response in Material. Jung Y. Huang 黃中垚 (http://www.jyhuang.idv.tw). Department of Photonics, Chiao Tung University August 6, 2009. An Overview.
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Architectural Photonics:A New Concept for Enhancing Opto-electronic Response in Material
Jung Y. Huang 黃中垚(http://www.jyhuang.idv.tw)
Department of Photonics, Chiao Tung University
August 6, 2009
At the nanometer scales, the ratio of the numbers of atoms at the surface and in the bulk of a material increases rapidly. Interfacial properties of a nanostructured material could, therefore, enable new functional materials or devices.
This is the new dimension we are exploring.
We are concerning how to tailor an existing material for an improved performance in a specific application.
In this talk, an architectural photonics, a new concept for enhancing opto-electronic response in material is proposed,
which is useful for optical detection and photovoltaic application.
Electronic Structure of nc-Si/MS
The QDs in an ensemble have different sizes, resulting in a distribution of the quantum-confinement energy spacing.
If there are no other nonradiative couplings, photo-excited carriers in anyQD eventually relax to the lowest levels and recombine togeneratea PL spectrum of a broad distribution of the lowest optical transition.
Two mechanisms can relax the crystal momentum conservation criterion for an optical transition:
The greater the charge density of the captured electron, the greater the force on the nearby ions and hence the larger the lattice relaxation.
Stokes Shift of nc-Si/MS
nc Si/MS PD
Hole trapping in the illuminated gate produces a built-in potential that adds to an external bias (Vg) to generate a negative shift (Vth) of threshold voltage, therefore, yields a higher drain current.
A strategy to realize 3D artificial crystal with both optical and magnetic activities:
Unfortunately, the distance between two closest nano particles is too large to allow the appearance of ferromagnetism.
TEM image of an array of 5-nm nc-Au capped with dodecanethiol.
Sketch of a nc-CdSe capped with Sn2S64– ions
TEM image of a three-dimensional superlattice of 5-nm nc-Au
capped with (N2H5)4Sn2S6.
Self-assembled Artificial Crystal of Nanoparticles
M. V. Kovalenko, et al.
Science 324, 1417 (2009)
Optical excitation in a semiconductor nanocrystal can delocalize in the artificial crystal.
The artificial crystalline film was invoked to be the channel of a MOSFET. Combined functionality of transistor amplification and optical response was revealed.