Materials Sciences and Applications, 2011, 2, 1302-1306
doi:10.4236/msa.2011.29176 Published Online September 2011 (http://www.SciRP.org/journal/msa)
Effect of Calcinations Temperature on
Crystallography and Nanoparticles in ZnO Disk
Urai Seetawan1, Suwit Jugsujinda1, Tosawat Seetawan1*, Ackradate Ratchasin1,
Chanipat Euvananont2, Chabaipon Junin2, Chanchana Thanachayanont2, Prasarn Chainaronk3
1Thermoelectrics Research Center, Faculty of Science and Technology, Sakon Nakhon Rajabhat University, Sakon Nakhon, Thailand;
2National Metal and Materials Technology Center, National Science and Technology Development Agency, Pathumthani, Thailand;
3Program of Physics, Faculty of Science, Ubonratchathani Rajabhat University, Ubon Ratchathani, Thailand.
Received April 22nd, 2011; revised May 30th, 2011; accepted June 7th, 2011.
ABSTRACT
We proposed a good calcinations condition of the ZnO disk to control the crystallography and nanoparticles in ZnO
disk. The crystallography of precursor powder and disk powder were analyzed by the X-ray diffraction (XRD). The
mean nanoparticles of ZnO disk was determinate by XRD results and observed by scanning electron microscope. The
temperature ranges of 400˚C to 650˚C in air for 30 minutes were used calcinations ZnO disk. These temperature can be
controlled the single phase, lattice parameters, unit cell volume, crystalline size, d-value, texture coefficient and bond
lengths of Zn–Zn, Zn–O and O–O which correspond significantly the hexagonal crystal structure. The nanoparticles
were small changed mean of 76.59 nm at the calcinations temperature range.
Keywords: Nanoparticles in ZnO Disk, Calcinations Temperature, Crystallography of ZnO
1. Introduction
Zinc oxide nanomaterials are interesting and have been
developed in recent years because of their physical and
chemical properties, which promote an achievement of
high performance materials for various applications. Re-
cently, many studies have been made in order to under-
stand the microstructure, electrical properties and ther-
moelectric properties of ZnO for application. For exam-
ples, the varistor ceramics [1], luminescent materials [2],
new coplanar gas sensor array [3], application of sun-
screen nanoparticles [4] and, finally, impure ZnO materi-
als are of great interest for high temperature thermoelec-
tric application [5].
In this work, we report an analysis the effect of calci-
nations temperature on phase identification, lattice pa-
rameters, crystal structure, orientation, texture coefficient,
bond length of Zn–Zn, Zn–O and O–O, powder distribu-
tion and powder size in ZnO disk for control the
nanopowder in ZnO disk or tendency apply the ZnO disk
to thermoelectric material.
2. Experimental
The ZnO precursor of nanopowder was synthesized by di-
rect precipitation method using Zn(NO3)2 ฺ·6H2O (QRëCTM,
98.5% purity), (NH4)2CO3 (QRëCTM, 99.5% purity),
ethanol, and de-ionized water. Firstly, Zn(NO3)2 ฺ·6H2O
and (NH4)2CO3 were dissolved in de–ionized water by
the vigorously stirring to form solutions with 1.5 and
2.25 mol/L concentrations, respectively. Secondly, the
precipitates obtained by the reaction between the
Zn(NO3)2 and the (NH4)2CO3 solutions were collected by
filtration and rinsed three times with de–ionized water
and ethanol, respectively, then washed and dried at 80˚C
to form the precursor of nanopowder. The calcinations
temperature was investigated by the relationship between
the weight loss and temperature by using thermal gra-
vimetric analysis (TGA–DTA/DSC; NETZSCH STA
449C). Finally, the precursor of nanopowder was pres-
sured by the hydraulic press about 160 MPa in air to ob-
tain the ZnO disk. The disk was calcinated at temperature
range 400˚C to 650˚C in air for 30 minutes. The crystal-
lography of precursor of powder and disk powder were
analyzed by X–ray diffraction (XRD; PW1710) with a
Cu–K1( = 0.15406 nm) source at 40 kV and 30 mA.
The morphology of the precursor of powder and disk
powder were observed by a scanning electron micro-
scope (SEM; JSM–6100). The particle size (D) of pre-
cursor and disk powder were calculated by the Debye–

Effect of Calcinations Temperature on Crystallography and Nanoparticles in ZnO Disk1303
Scherrer formula using raw data from XRD patterns and
evaluated from SEM images. The crystalline size was
calculated by the Debye–Scherrer formula as follows.
0
0.89
cos
D



 (1)
where is the crystalline size (in nm), D

is the
wavelength (in nm),

is the full width at half maxi-
mum (FWHM–in radian) intensity, and

is the Bragg
diffraction angle [6]. The relative percentage error for all
the disks was evaluated by the Equation (2) and JCPDS
standard d-values [7].
Relative percentage error 100
H
ZZ
Z

 (2)
where
H
Z
is the actual obtained d-value in XRD pat-
terns and
Z
is the standard d-value in JCPDS data. The
particular plane and information were concerned by the
preferential crystallite orientation determined from the
texture coefficient [8] as follows:

TC hkl

 

0
1
0
100%
n
Ihkl I hkl
TC hklNIhklIhkl




(3)
where

I
hkl

hkl
is the measured relative intensity of a
plane , and

0

I
hkl is the standard intensity of
the plane taking from the JCPDS data [9,10]. The Zn–O
bond length is given by

L
2
2
21
32
a
Lcu

 


(4)
where the parameter is defined by u
2
20.25
3
a
uc  ,
a and b are lattice parameters [11]. The unit cell
structure was designed by discrete variational X

me-
thod for evaluating Zn–O bond length [12]. The volume
of hexagonal primitive cell is 2
3
2ac



 and Brillouin
zone is where is the volume of a crystal
primitive cell [13].

3
2πc Vc V
3. Results and Discussion
The TGA curve shows a weight loss step at incremented
temperatures from 25˚C to 1000˚C as shown in Figure 1.
The weight loss was related to the decomposition of the
precursor of powder. The clear plateau was formed in a
temperature range between 435˚C and 650˚C on the TGA
curve indicate the calcinations temperature range to con-
trol weight loss and save ZnO disk. No further weight
loss and no thermal effect were observed at temperatures
100 200 300 400 500 600700 800 9001000
99.0
99.5
100.0
100.5
101.0
Weight Loss (%)
Temperature (oC)
Change 0.17%
DTA (mW/mg)
Change 0.15%
0
5
10
15
20
435
Figure 1. TGA–DTA traces at a heating rate of 10˚C/min
for ZnO precursor of powder.
range 435˚C to 500˚C indicating that decomposition does
not occur above this temperature and the stable nanopar-
ticles. The XRD patterns of the precursor of powder were
corresponded the patterns of JCPDS Card No.891397.
The precursor of powder has been the lattice parameters
a = b = 3.2481 Å, c = 5.2049 Å indicate hexagonal
structure.
Therefore, we should the temperature range of 400˚C
to 700˚C for calcinations the ZnO disk to control the
nanoparticles. However, the disk has agglomerated pow-
der and cracked at 700˚C.
The XRD patterns of the disk powder were calcinated
at temperatures of 400˚C, 450˚C, 500˚C, 550˚C, 600˚C
and 650˚C in air for 30 minutes are shown in Figure 2(a)-
2(f), respectively. The main peaks correspond to the
hexagonal structure ZnO and the lattice constants a = b =
3.2469 Å increase to 3.2488 Å and c = 5.2049 Å slightly
decrease to 5.2031 Å as shown in Figure 3.
The values of ca and unit cell volume were corre-
sponded to literature data [14-17] as shown in Figure 4.
The full widths at half maxima (FWHM) of the (100),
(002) and (101) index planes of 0.256, 0.256 and 0.26
nm, respectively, were uses for particle size calculation.
The d–values, d% error and texture coefficient calcu-
lated by using Equation (2) and (3) are shown in Table
1.
The average relative percentage errors of calcinations
temperatures of 400˚C, 450˚C, 500˚C, 550˚C, 600˚C and
650˚C are 0.17%, 0.77%, 0.28%, 0.18%, 0.59%, and
0.29%, respectively. The experimental d-values and
JCPDS d-values are in a good agreement and indicate
hexagonal structure [9].
The texture coefficient (TC (h k l)) values were calcu-
lated by Equation (3) and obtain a mean value of 0.35.
The value TC (h k l) = 1 represents randomly oriented
crystallites, while higher values indicate the abundance
of grains oriented in a given (h k l) direction. According

Effect of Calcinations Temperature on Crystallography and Nanoparticles in ZnO Disk
1304
(f)
(203)
(104) (202)
(004)
(201)
(112)
(200)
(103)
(110)
(102)
(101)
(002)
(100)
(e)
(d)
Intensity (a. u.)
(c)
(b)
30 35 40 45 50 5560 65 70 75 80 85 90
2 (degree)
(a)
Figure 2. XRD patterns of disk ZnO powder calcinated at (a)
400˚C, (b) 450˚C, (c) 500˚C, (d) 550˚C, (e) 600˚C and (f) 650˚C.
350 400 450 500 550 600 650 700
3.244
3.245
3.246
3.247
3.248
3.249
Lattice Const an t c (Å)
Lattice Constant a (Å)
Calcinations Temperature ( oC)
5.201
5.202
5.203
5.204
5.205
5.206
5.207
5.208
Figure 3. The calcinations temperature dependence on the
lattice constants, a and c.
to Equation (2), we know that the (1 0 0), (0 0 2) and (1 0
1) planes were the preferential crystallite orientation for
the nanopowder of ZnO fabricated in this work. The TC
(h k l) represents the texture of a particular plane, whose
deviation from unity implies the preferred growth [18]. It
400 450 500 550 600 650
1.6015
1.6020
1.6025
1.6030
Unit Cell Volume (Å3)
c/a
Calcinations Temperature (oC)
47.50
47.51
47.52
47.53
47.54
47.55
47.56
47.57
Figure 4. The calcinations temperature dependence on the
ratio of c/a lattice constants and unit cell volume.
Table 1. 2θ, d–value, calculation d% error and texture coef-
ficient of the (101) for disk ZnO powder after calcinations.
Sin. Temp. 2θ d (Å) d (%) TC
400 36.277 2.4743 0.17 0.32
450 36.504 2.4594 0.77 0.38
500 36.317 2.4716 0.28 0.32
550 36.282 2.474 0.18 0.33
600 36.398 2.4663 0.59 0.33
650 36.324 2.4712 0.29 0.32
can be seen that the highest TC was in the (101) plane for
nanopowder in ZnO disk at 450˚C [19].
The bond lengths of Zn–Zn, Zn–O and O–O are shown
in Table 2, where the Zn–O bond length is 1.9767 Å in
the unit cell of ZnO and neighboring atoms. Viewing
direction is approximately parallel to O2− and Zn2+ cor-
responding to literature data [20] and have a good ther-
moelectric power about −279 µV/K at 500˚C [21] which
is close to the proposed calcinations temperature range.
The SEM images of nanopowder in ZnO disk after
calcinations temperature of 400˚C, 450˚C, 500˚C, 550˚C,
600˚C and 650˚C, respectively are shown in Figure 5(a)-
5(f).
The nanopowder of ZnO was exhibited a good distri-
bution after being calcinated below 550˚C. The powder
of ZnO was covered with nanopowder, while other por-
tions retained the smooth morphology. The particle sizes
were small increased from 73.50 to 79.67 nm with in-
creasing calcinations temperature as shown in Figure 6.
However, the nanopowder was agglomerated to form
larger particle sizes at the calcinations temperature higher
than 650˚C and disk fractured at 700˚C.

Effect of Calcinations Temperature on Crystallography and Nanoparticles in ZnO Disk1305
Table 2. The bond length lists of ZnO compound.
1
th (Å) 2nd (Å) 3th (Å) 4th (Å) 5th (Å)
Zn–Zn 3.2138 3.2568 4.5755 5.2125 5.6162
Zn–O 1.9767 1.9959 3.2166 3.8099 3.8197
O–O 3.2138 3.2568 4.5755 5.2125 5.6162
(a) (b)
(c) (d)
(e) (f)
400 C450 C
500 C550 C
600 C650 C
Figure 5. SEM morphology of ZnO disk powder after cal-
cinated at (a) 400˚C, (b) 450˚C, (c) 500˚C, (d) 550˚C, (e)
600˚C and (f) 650˚C.
400 450 500 550 600 650
73
74
75
76
77
78
79
80
81
Particle Size (nm)
Calcinations Temperature (oC)
Figure 6. The calcinations temperature dependence on par-
ticle sizes of ZnO disk powder.
4. Conclusions
The temperature range of 400˚C to 650˚C was chosen for
calcinations temperature and controled the nanoparticle
in ZnO disk. The crystallography of disk powder was
corresponding to the hexagonal structure and the lattice
constants. The experimental d–values were in a good
agreement with JCPDS I and indicated the hexagonal
structure. The Zn–O bond length of 1.9767 Å was related
with ZnO unit cell viewed direction approximate parallel
to O2− and Zn2+. The disk powder was exhibited good
distribution after being calcinated below 550˚C covering
with the nanoparticles, while other portions retained the
smooth morphology and the mean particle size of 76.59.
5. Acknowledgements
Financial support was provided by the Electricity Gener-
ating Authority of Thailand, EGAT (52-2115-043-JOB
No. 803-SNRU).
REFERENCES
[1] D. Xu, X. F. Shi, X. N. Cheng, J. Yang, Y. E. Fan, H. M.
Yuan and L. Y. Shi, “Microstructure and Electrical Prop-
erties of Lu2O3–Doped ZnO–Bi2O3–Based Varistor Ce-
ramics,” Transactions of Nonferrous Metals Society of
China, Vol. 20, No. 12, December 2010, pp. 2303-2308.
doi:10.1016/S1003-6326(10)60645-0
[2] N. Hagura, T. Ogi, T. Shirahama, F. Iskandar and K.
Okuyama, “Highly luminescent Silica–Coated ZnO Nano-
particles Dispersed in Anaqueousmedium,” Journal of
Luminescence, Vol. 131, No. 5, May 2011, pp. 921-925.
doi:10.1016/j.jlumin.2010.12.024
[3] C. Li, S. Zhang, M. Hu and C. Xie, “Nanostructural ZnO
Based Coplanar Gas Sensor Arrays from the Injection of
Metal Chloride Solutions: Device Processing, Gas-Sens-
ing Properties and Selectivity in Liquors Applications,”
Sensors and Actuators B, Vol. 153, No. 2, April 2011, pp.
415-420. .doi:10.1016/j.snb.2010.11.008
[4] A. P. Popov, A. V. Priezzhev, J. Lademann and R.
Myllylä, “Alteration of Skin Light–Scattering and Ab-
sorption Properties by Application of Sunscreen
Nanoparticles: A Monte Carlo Study,” Journal of Quan-
titative Spectroscopy & Radiative Transfer, 2011, Article
in Press.
[5] X. Qu, W. Wang, S. Lva and D. Jia, “Thermoelectric
Properties and Electronic Structure of Al–Doped ZnO,”
Solid State Communications, Vol. 151, No. 4, February
2011, pp. 332-336. doi:10.1016/j.ssc.2010.11.020
[6] C. Chen, B. Yu, J. Liu, Q. Dai and Y. Zhu, “Investigation
of ZnO Films on Si(111) Substrate Grown by Low En-
ergy O+ Assisted Pulse Laser Deposited Technology,”
Material Letters, Vol. 61, No. 14-15, June 2007, pp.
2961-2964.
[7] D. P. Padiyan and A. Marikani, “X–Ray Determination of
Lattice Constants of CdXSn1–XSe Mixed Crystal Sys-
tems,” Crystal Research and Technology, Vol. 37, No. 11,
November 2002, pp. 1241-1248.
doi:10.1002/1521-4079(200211)37:11<1241::AID-CRAT
1241>3.0.CO;2-C

Effect of Calcinations Temperature on Crystallography and Nanoparticles in ZnO Disk
1306
[8] C. S. Barret, T. B. Massalski, “Structure of Metals,” Per-
gamon Press, Oxford, 1980.
[9] Joint Committee on Powder Diffraction Standards, Pow-
der Diffraction File, Card No: 891397.
[10] H. Schulz and K. H. Thiemann, “Structure Parameters
and Polarity of the Wurtzite Type Compounds Sic–2H
and ZnO,” Solid State Communications, Vol. 32, No. 9,
December 1997, pp. 783-785.
[11] S. Aksoy, Y. Caglar, S. Ilican and M. Caglar, “Effect of
Deposition Temperature on the Crystalline Structure and
Surface Morphology of ZnO Films Deposited on p–Si,”
Advances in Control, Chemical Engineering, Civil Engi-
neering and Mechanical Engineering,
ISBN: 978–960–474–251–6, pp. 227-231.
[12] H. Adachi, M. Tsukada and C. Satoko, “Discrete Varia-
tional Xα Cluster Calculations. I. Application to Metal
Clusters,” Journal of the Physics Society of Japan, Vol.
45, April 1978, pp. 875-883.
[13] C. Kittel, “Introduction to Solid State Physics,” 8th Edi-
tion, John Wiley & Sons, New York, 2005.
[14] R. Chowdhury, P. Rees, S. Adhikari, F. Scarpa and S. P.
Wilks, “Electronic Structures of Silicon Doped ZnO,”
Physica B, Vol. 405, No. 8, April 2010, pp. 1980-1985.
doi:10.1016/j.physb.2010.01.084
[15] S. Panpan, S. Xiyu, H. Qinying, L. Yadong and C. Wei,
“First-Principles Calculation of the Electronic Band of
ZnO Doped with C,” Journal of Semiconductors, Vol. 30,
No. 5, May 2009, pp. 052001-1-052001-4.
[16] E. H. Kisi and M. M. Elcombe, “u Parameters for the
Wurtzite Structure of ZnS and ZnO Using Powder Neu-
tron Diffraction,” Acta Crystallographica Section C—
Crystal Structure Communications Vol. 45, No. 12, De-
cember 1989, pp. 1867-1870.
[17] J. L. Lyons, A. Janotti and C. G. Van de Walle, “Role of
Si and Ge as Impurities in ZnO,” Physical Review B, Vol.
80, No. 20, November 2009, pp. 205113-2051117.
doi:10.1103/PhysRevB.80.205113
[18] C. S. Barret and T. B. Massalski, “Structure of Metals,”
Pergamon Press, Oxford, 1980.
[19] S. Ilican, M. Caglar and Y. Caglar, “Determination of the
Thickness and Optical Constants of Transparent Indium-
Doped ZnO Thin Films by the Envelope Method,” Mate-
rials Science—Poland, Vol. 25, No. 3, April 2007, pp.
709-718.
[20] O. Altuntasoglu, Y. Matsuda, S. Ida and Y. Matsumoto,
“Syntheses of Zinc Oxide and Zinc Hydroxide Single
Nanosheets,” Chemistry of Materials, Vol. 22, No.10,
April 2010, pp. 3158-3164. doi:10.1021/cm100152q
[21] X. Qu, W. Wang, S. Lv and D. Jia, “Thermoelectric
Properties and Electronic Structure of Al-Doped ZnO,”
Solid State Communications, Vol. 151, No. 4, February
2011, pp. 332-336. doi:10.1016/j.ssc.2010.11.020