Research Progress

Effect of silver evolution on conductivity 
and transmittance of ZnO/Ag thin films
JournalJournal of Applied Physics
Author: Dongyan Zhang, Hiromi Yabe, Eri Akita, Pangpang Wang,  Ri-ichi Murakami, and Xiaoping Song
    ZnO films with an embedded silver layer, one of the most promising transparent conductive materials, possess excellent conductivity and optical transmittance. The performance of ZnO films is greatly affected by the morphology of the silver layer. In this work, we studied the changes in the electrical and optical properties of ZnO/Ag multilayered films as a function of the coalescence of the silver clusters. Silver clusters aggregated into various morphologies at different layer growth stages and dominantly affected the conductivity of ZnO/Ag films as a result of different electron transport mechanisms. The optical transmittance was also enhanced by surface plasmon resonance between the incident light and the random grating of the silver clusters. The improved electrical conductivity and optical transmittance give asymmetric ZnO/Ag multilayered films the potential to be used as transparent electrodes.

Conclusion
    In conclusion, high transmittance ZnO/Ag multilayered films with low resistivity were obtained that are promising candidates for TCO applications. The dependence of the electrical and optical properties on the silver layer structure was investigated.
    1. The morphological changes of the silver layer in ZnO/Ag multilayered films were divided into different stages—from separated islands to semicontinuous layer with holes.
    2. The electrical conductivity was governed by the different electron transport mechanisms because of the change in silver layer morphology. An obvious change of conductivity was observed at the silver thickness of 6 nm, and the ZnO/Ag films with 12-nm-thick silver layer showed a low sheet resistance of 2.31 Ω/□.
    3. The optical transmittance of the ZnO/Ag film was enhanced close to 90% by the SPR of the incident light with the silver island random grating. The bandgap of ZnO was diminished because of the SPR at the ZnO/Ag interface.

Resistivity and sheet resistance of the ZnO/Ag multilayered films on the glass substrate as a function of the silver layer thickness. 


The exposure time for Ag sputtering is also indicated at the top of the figure

TEM images of coalesced silver islands (Stage Ⅱ). 
The red circles indicate the silver islands.
(a) The silver islands coalesced into a network structure. 
(b) A magnified image of the silver island combination.
(c) Crystalline silver with a 2.502 Å lattice constant.
 The arrow indicates the lattice spacing.
Large Magnetostriction from Morphotropic Phase Boundary in Ferromagnets
Journal:PHYSICAL REVIEW LETTERS, 104, 197201 (2010)
Author:  Sen Yang, Huixin Bao, hao Zhou, Yu Wang, Xiaobing Ren,  Yoshitaka Matsushita, Yoshio Katsuya, Masahiko Tanaka, Keisuke Kobayashi, Xiaoping Song, and Jianrong Gao
      For more than half of a century, morphotropic phase boundary (MPB) in ferroelectric materials has
drawn constant interest because it can significantly enhance the piezoelectric properties. However, MPB
has been studied merely in ferroelectric systems, not in another large class of ferroic systems, the
ferromagnets. In this Letter, we report the existence of an MPB in a ferromagnetic system TbCo2-DyCo2.
Such a magnetic MPB involves a first-order magnetoelastic transition, at which both magnetization
direction and crystal structure change simultaneously. The MPB composition demonstrates a 3–6 times
larger ‘‘figure of merit’’ of magnetostrictive response compared with that of the off-MPB compositions.
The finding of MPB in ferromagnets may help to discover novel high-performance magnetostrictive and
even magnetoelectric materials.
Morphotropic phase boundary (MPB) in a ferroelectric PZT system (PbZrO3-PbTiO3) and in a ferromagnetic
TbCo2-DyCo2 system. (a) Phase diagram of PZT (Ref. [1] p. 136). (b) Phase diagram of TbCo2-DyCo2. (c) Temperature dependent of ac susceptibility. Tc and TM denote para-ferro and ferro-ferro transition temperature, respectively. (d) Synchrotron XRD profiles of cubic paramagnetic phase, rhombohedral ferromagnetic phase, and tetragonal ferromagnetic phase.
Composition dependent of physical properties
in relation with MPB composition at 110 K. 
(a) ac susceptibility, (b) saturation magnetization Ms, (c) coercivity Hc,  (d) magnetostriction " (absolute value) at 10 kOe field,  (e) figure of merit "=Hc, (f ) magnetic hysteresis loops, (g) magnetostriction
curves.
Ag–Sb composite prepared by chemical reduction method as new anode
materials for lithium-ion batteries
Journal:Materials Science and Engineering B 176 (2011) 442–445
Author:  Fei Wang, Gang Yao, Minwei Xu, Mingshu Zhao, Peixin Zhang, Xiaoping Song
Ag–Sb composite anode was prepared by chemical reductive method. The structure, morphology, chemical
composition and electrochemical properties of synthesized Ag–Sb composite anode were evaluated
by XRD, FE-SEM, EDS and galvanostatical charge–discharge tests. The results indicated that the changes
of structure and volume were alleviated effectively by using metal phase instead of intermetallic phase
and restraining the lithiation reaction of Ag at high current density (0.2mAcm−2). The electrochemical
reactions took place in a stable and highly conductive Ag framework, which ensured the good cyclability
of the Ag–Sb composite electrode.
FE-SEM images of Sb (a), Ag (b) and Ag–Sb composite (c); EDS spectrum of Ag–Sb composite (d).
Cycling performances of Ag–Sb composite tested at different current densities and Sb tested at 0.1mAcm−2 (inset).
Nanoparticle-aggregated paddy-like copper dendritic nanostructures
Journal: CrystEngComm, 2011, 13, 1916–1921
Author: Shaodong Sun, Chuncai Kong, Liqun Wang, Shengchun Yang, Xiaoping Song, Bingjun Ding and Zhimao Yang
   In this paper, an HCuCl2 solution has been discovered for high-yield fabrication of paddy-like copper
dendritic nanostructures via electroless deposition route. The morphology of the copper dendritic
nanostructure is obviously better than that synthesized in CuCl2 aqueous solution under otherwise the
same experimental conditions. The appearance of these novel paddy-like copper nanodendrites can be
attributed to diffusion-limited aggregation and oriented attachment mechanism. The dendritic
morphology can be tailored via physical field, such as thermal field and magnetic field. Significantly, the
HCuCl2 solution reported in this work might provide a new way for the shape-controlled synthesis of
metal copper or copper based alloy.
 
FE-SEM images of the products of synthesized in a higher concentration of HCuCl2 solution (Cu2O, 0.0144 g; HCl 2 mL, 2 M) at different reaction time. (a) 1 s; (b) 3 s; (c) 5 s; (d) 10 s; (e) 15 s; (f) 30 s.
(a) TEM image of a trunk tip as shown in location II of Fig. 4a; (b) HRTEM image of red circle as shown in (a).
Designated-Tailoring on {100} Facets of Cu2O Nanostructures:
From Octahedral to Its Different Truncated Forms
Journal: Journal of Nanomaterials
Author:  Zhimao Yang, Shaodong Sun, Chuncai Kong, Xiaoping Song, and Bingjun Ding
   A facile template-free controlled synthesis of Cu2O architectures from octahedral to its different truncated forms is successfully achieved. It is found that the precursor formation temperature is crucial to the designated-tailoring on the {100} facets of Cu2O crystals, which can modify the ratio (R) between the growth rates along the 100 and 111 directions, leading to the formation of the initial structures with different shapes. The multiple morphologies can be evolved from these varied initial structures via the synergic effect of oriented attachment and ripening mechanism. This template-free complex precursor-based solution route has provided an innovative approach to design the {100} facets with different sizes to further enrich the current morphologies of Cu2O crystals.
FESEM images of (a) sample S1, (b) sample S2, and (c) sample S3. The inserts are the corresponding schematic illustrations.
A schematic illustration of the proposed particle growth mechanism and reaction pathways that lead to the formation of Cu2O crystals with different polyhedral shapes. As the essence of our synthesis, the precursors with different properties can be reduced by C6H12O6 to form Cu2O particles, which subsequently aggregate to form different initial structures. Subsequently, these initial structures will grow into various polyhedral forms through the synergic effect of oriented attachment and ripening mechanism, which can modify the ratio (R)
between the growth rates along the 100 and 111 directions.