2008 NSTI Nanotechnology Conference and Trade Show - Nanotech 2008 - 11th Annual

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Clean Technology 2008

Visible-band optical sensor based on CdSxSe1-x nanobelts

Y.-J. Choi, J.-G. Park, D.-W. Kim, K.J. Choi
Korea Institute of Science and Technology, KR

Keywords:
nanostructures, nanobelts, optical sensor, CdSxSe1-x

Abstract:
We report on the synthesis and optical-sensor application of CdSxSe1-x (x=0, 0.25, 0.5, 0.75, and 1) nanobelts synthesized by a pulsed laser deposition (KrF excimer laser, 248nm). X-ray diffraction analysis showed that the CdSxSe1-x nanobelts were single crystalline in wurtzite structure. The diffraction peaks were shifted toward the higher 2 value with the increase of sulphur composition, which indicates that the lattice constant and unit cell volume scales linearly with the composition. In photoluminescence measurements, we found that the direct bandgap energy of the nanobelts changes linearly with the composition. These results suggest that the bandgap energy of the CdSxSe1-x nanobelts can be systematically modulated in the spectral range from 1.74 to 2.45 eV. And finally, we successfully fabricated visible-band optical sensors using CdSxSe1-x nanobelts. For fabricating optical sensors, we dispersed CdSxSe1-x nanobelts on inter-digitized electrodes, which were prepared by a conventional photolithographic process and subsequent Cr/Au metallization on the glass substrate. The cut-off frequency of the optical sensor was observed to shift toward longer wavelength region with the increase in the sulphur composition.


Nanotech 2008 Conference Program Abstract