Photonic crystals in biology

Poster Session, Tuesday, June 15
Theme A1 - B702
Preparing ZnO:Mn Nanoparticles: A Comparison Between Sol Gel and Gel Combustion Method
Majid Ebrahimizadeh Abrishami, 1 Seyed Mohammad Hosseini 1 , Ebrahim Attaran Kakhki 1 and Mahdi Ghasemifard 1
1 Matterials and Electroceramics Lab., Department of Physics, Ferdowsi University, Mashhad, Iran
Abstract— We prepared ZnO:Mn nanoparticles using two different routes which are sol gel and gel combustion. TEM images
showed that the size of nanoparticles, prepared using gel combustion method, were 40% smaller than the other. The effect of
synthesis process on structural and optical properties was investigated by XRD analysis and UV absorbance spectra.
Zinc oxide (ZnO) holds a great position in fabricating the
electronic devices due to remarkable electrical and optical
properties such as piezoelectricity, controllable conductivity,
large band gap energy (3.3eV), transparency in the visible
range and etc [1,2]. Furthermore, ZnO is considered for
spintronics applications with magnetic ions (Co, Ni, V, Fe and
Mn) doping. In this direction, Mn doped ZnO has became a
reasonable choice for Diluted Magnetic Semiconductors
(DMS). Even, ferromagnetic state was reported below and
above room temperature [3]. However, in recent years,
synthesis of nanopowders of ZnO, MnO and doping ZnO with
transition metals by different routes such as wet chemical
methods like sol-gel [4], co-precipitation [5], and combustion
[6] in nanotechnology is custom in worldwide.
In this work, Zn 1-x Mn x O (x = 0.00, 0.06 and 0.10)
nanoparticles were synthesized using two different wet
chemical methods which are sol gel and gel combustion. The
starting materials were comprised of zinc and Mn acetates,
diethanolamine and acetic acid. Process of preparing cations
solution with no particulates and precipitates, stable sol and
clear gel in both methods were similar. In the sol gel method,
the acceptable gel was fired directly on hot plate and
calcinated at 400C. But, we synthesized the ZnO:Mn
nanopowders with adding nitric acid as a fuel, in gel
combustion method.
TEM images presented that the ZnO:Mn nanoparticles,
prepared using gel combustion method, were smaller in size.
As shown in Figure, the acceptable homogeneity in size
distribution and spherical shapes of particles were clearly
observed in samples prepared using two different routes.
Next, we investigated the structural properties of
nanopowders using X-ray diffractometer. XRD patterns
showed that all the samples were crystallized in single phase
wurtzite structure and no impurity phases were explored. In
other words, the Mn solubility was clearly increased.
Furthermore, the Full Width at Half Maximum (FWHM) of
XRD reflection peaks were more broadened in samples
prepared using gel combustion method. In addition, XRD
analysis confirmed that the growth in Mn concentration
resulted in increasing lattice parameters in samples
synthesized using both techniques.
Also, we consider the optical properties using UV
diffractometer. UV absorbance spectra of all nanopowders
have only one characteristic peak which is gradually shifted to
lower wavelengths with increasing Mn content. This peak
illustrates the optical absorbance edge. In this case, we
determined the optical band gaps E g of samples using Morales
approach [7]. This investigation showed the decreasing E g
with increasing Mn content. However, the values for E g ,
extracted from UV absorbance spectra of nanoparticles
prepared using gel combustion method, were more severely
decreased with increasing Mn content.
Table. The variation in structural and optical properties of ZnO:Mn
nanopowders due to Mn doping and synthesis process.
Sol gel
Gel Combustion
Mn content (x) 0.00 0.06 0.10 0.00 0.06 0.10
latt. const. a (Å) 3.247 3.248 3.249 3.246 3.247 3.248
latt. const. c (Å) 5.198 5.201 5.202 5.196 5.199 5.201
absorb. edge (nm) 379.9 382.9 385.9 370.0 395.0 410.0
E g (eV) 3.22 3.14 3.12 3.22 3.10 3.02
Figure: TEM images of ZnO nanoparticles prepared using (a) sol gel
method. (b) gel combustion method.
In summary, we showed that different routes to prepare
nanoparticles have effect on structural and optical properties.
Our results open a new window to control the synthesis
process, size of particles, lattice constant changes and band
gap energy variations and etc.
*Corresponding author: ebrahimizadeh@ymail.com
[1]M. Ohtaki, K. Araki and K. Yamamoto, J. Elect. Mater. 38, 1234
(2009).
[2]S. S. Kwon, W. K. Hong, G. Jo, J. Maeng, T. W. Kim, S. Song and
T. Lee, Adv. Mater. 20, 4557 (2008).
[3]M. Ebrahimizadeh Abrishami, S. M. Hosseini, E. Attaran Kakhki
and A. Kompany, Mod. Phys. Lett. B, in press (2010).
[4]Q. Xu, S. Zhou and H. Schmidt, J. Allo. and Comp.,
doi:10.1016/j.jallcom.2009.08.033.
[5] R. S. Yadav, A. C. Pandey, S. S. Sanjaya, Chalcogenide Lett. 6,
233 (2009).
[6]N. Riahi-Noori, R. Sarraf-Mamoory, P. Alizadeh and A.
Mehdikhani , J. Ceram. Process. Res. 9, 246 (2009).
[7]A. E. Morales, E. S. Mora and U. Pal, Revista Mexicana de
F´isicas, 53, 18 (2007).
6th Nanoscience and Nanotechnology Conference, zmir, 2010 288