ORIGINAL PAPER
Structure and dielectric properties of 80%Pb(Zn
1/3
Nb
2/3
)
O
3
–20%PbTiO
3
thin films prepared by modified sol–gel process
Chuanqing Li
•
Aiyun Liu
•
Junqiang Shi
•
Yafei Ruan
•
Lei Huang
•
Wangzhou Shi
•
Xiangjian Meng
•
Jinglan Sun
•
Junhao Chu
•
Xiaodong Zhang
Received: 20 April 2011 / Accepted: 2 September 2011 / Published online: 14 September 2011
Ó Springer Science+Business Media, LLC 2011
Abstract 80%Pb(Zn
1/3
Nb
2/3
)O
3
–20%PbTiO
3
(PZN–PT)
thin films have been prepared on Pt/Ti/SiO
2
/Si substrates
using a modified sol–gel method. In our method, niobium
pentaoxide is used as a substitution instead of niobium
ethoxide which is moisture-sensitivity and much more
expensive. Microstructure and electrical properties of
PZN–PT thin films have been investigated. X-ray diffrac-
tion analysis shows that proper annealing temperature of
PZN–PT thin films is 600 °C. The PZN–PT thin films
annealed at 600 °C are polycrystalline with (111)-prefer-
ential orientations. Field-emissiom scanning electron
microscope analysis revealed PZN–PT thin films possess
well-defined and crack-free microstructure. The thickness
of thin films is 290 nm. The Pt/PZN–PT/Pt capacitors have
been fabricated and it presents ferroelectric nature. The
remanent polarization (Pr), spontaneous polarization (Ps),
and the coercive electric field (Ec) are 8.71 lC/cm
2
,
43.06 lC/cm
2
, and 109 kV/cm at 1 MHz, respectively.
The dielectric constant (e
r
) and the dissipation factor (tan d)
are about 500.3 and 0.1 at 1 kHz, respectively.
Keywords PZN–PT Ferroelectric thin film Modified
sol–gel process
1 Introduction
In recent years, the development of science and technology,
ferroelectric thin films have represented a very important area
in the material sciences field. The reason is that it can be
achieved integration criteria easily and applied in a variety of
integrated devices, e.g. electro-optic devices, dynamic ran-
dom access memories (DRAM), pyroelectric devices, non-
volatile memory devices, and micro-electromechanical
devices for its excellent ferroelectric, pyroelectric, and pie-
zoelectric properties [1–6]. This has stimulated numerous
investigations of the thin-film preparation of lead-based
perovskite ferroelectrics, such as PbTiO
3
(PT), Pb(Zr
1-x
Ti
x
)
O
3
(PZT), (1 - x) Pb(Mg
1/3
Nb
2/3
)O
3
–xPbTiO
3
(PMN–
PT)[1–3]and(1 - x)Pb(Zn
1/3
Nb
2/3
)O
3
–xPbTiO
3
(PZN–PT).
Among these materials, PZN–PT is one of the most interesting
ferroelectric materials for its high dielectric permittivity, an
extraordinary large piezoelectric strain ([0.6%), piezoelectric
constant (d
33
[2500 pC/N), and a very high electro-
mechanical coupling factor (k
33
[90%) [7–15]. However, the
dielectric constant of the derived thin films is usually much
smaller than that of its single crystals or ceramics, and the
reason is proposed to be associated with the microstructure,
orientation, and crystallinity of the films [16–18].
In addition, lead zinc niobate Pb(Zn
1/3
Nb
2/3
)O
3
(PZN) and
lead titanate PbTiO
3
(PT) can form a complete solid solution
(1 - x)Pb(Zn
1/3
Nb
2/3
)O
3
–xPbTiO
3
(PZN–PT). The (1 - x)
PZN–xPT solid solution has a morphotropic phase boundary
(MPB) where x is around 10 mol% [19]. (1 - x)PZN–xPT
single crystal with a MPB composition exhibits excellent
C. Li A. Liu (&) J. Shi Y. Ruan L. Huang W. Shi
Department of Physics, Shanghai Normal University,
100 Gui Lin Road, Shanghai 200234,
People’s Republic of China
e-mail: liuaiyun2000@163.com
X. Meng J. Sun J. Chu
National Laboratory for Infrared Physics, Shanghai Institute
of Technical Physics, Chinese Academy of Sciences, 500 Yutian
Road, Shanghai 200083, People’s Republic of Chin
X. Zhang
Department of Ceramics and Glass Engineering and CICECO,
University of Aveiro, 3810-193 Aveiro, Portugal
123
J Sol-Gel Sci Technol (2011) 60:164–169
DOI 10.1007/s10971-011-2575-8