Physical properties of ZnSe and CdSe semiconductor nanoparticles synthesized by thermal treatment and gamma irradiation routes
Several methods have been utilized previously to synthesize metal chalcogenide nanoparticles with enhanced chemical and physical properties. However, most of these methods have used a complicated procedure, longer reaction times, and employed toxic reagents of expensive materials. Current study e...
Saved in:
| Main Author: | |
|---|---|
| Format: | Thesis |
| Language: | English |
| Published: |
2016
|
| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/69300/1/FS%202016%2083%20IR.pdf |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Summary: | Several methods have been utilized previously to synthesize metal chalcogenide
nanoparticles with enhanced chemical and physical properties. However, most of these
methods have used a complicated procedure, longer reaction times, and employed
toxic reagents of expensive materials. Current study employed two physical methods,
the thermal treatment to synthesis pure ZnSe and CdSe semiconductor nanoparticles
and their (Cd0.5Zn0.5)Se nanocomposite under a constant N2 gas flow. Gamma
radiation method was used to prepare pure ZnSe and CdSe semiconductor
nanoparticles.
For the first method, an aqueous solutions of metal nitrate at different concentrations
were mixed with 2 g of PVP, ethylenediamine(en) as a solvent of Se and deionized
water as a solvent were prepared at calcination temperatures of 450-700°C. The
samples were characterized by TGA, FTIR, EDX, XRD, TEM, and UV-Vis. FTIR
analysis results confirmed the removal of organic matters and the presence of
semiconductor nanoparticles at calcination temperatures 450-700°C. The elemental
composition of the samples obtained by EDX spectroscopy has further evidence that
the formation of ZnSe and CdSe nanoparticles and their nanocomposites. It was found
that the phase formations of ZnSe and CdSe nanoparticles were cubic and hexagonal
face-centered, respectively. The TEM images confirmed the increment of particle size
from 12 to 26 nm for ZnSe and from 6 to 37 nm for CdSe and as well as from 12 to
24 nm for (Cd0.5Zn0.5)Se nanocomposites due to elevated calcination temperature and
material concentration. The particle size of nanocrystals was also determined from
XRD spectra. The estimated average sizes in the range 10.5-24 nm for ZnSe, 6-33 nm
for CdSe nanoparticles and 10.5-25 nm for (Cd0.5Zn0.5)Se nanocomposites. While the
optical properties were measured using UV-Vis spectrometer and the band gap ranged
(3.956-4.158), (2.31-3.69) and (2.24-3.71) eV for ZnSe, CdSe and (Cd0.5Zn0.5)Se
nanostructures, respectively. ZnSe and CdSe semiconductor nanoparticles were also synthesized using a single-step
radiolytic approach in aqueous solution containing metal sulfite were mixed with 2 g
of PVP, ethylenediamine(en), deionized water, and IPA alcohol under irradiation with
Co-60 gamma rays at dose of 120 kGy. The hydrate electrons created in water are
responsible for the formation of CdSe and ZnSe nanoparticles. The final samples were
characterized by EDX, XRD, TEM, and UV-Vis. The X-ray powder diffraction
patterns reveal successful hexagonal crystal structure for both CdSe and ZnSe
nanoparticles, with the average crystallite sizes of 16.3 and 10.7 nm, respectively. The
EDX was used to confirm the stoichiometric elemental composition of Zn, Cd and Se
in the samples. The TEM micrograph shows that CdSe and ZnSe nanoparticles are
spherical in shape, with an average diameter of 17.3 and 11.2 nm, respectively. The
optical band gaps determined from UV-Visible absorption spectra are between 2.87
and 3.58 eV for the CdSe and ZnSe nanoparticles, respectively. |
|---|