Conductive LaNiO3 (LNO) thin films were grown on Si substrates by metalorganic decomposition (MOD) and their application as the bottom electrodes for the growth of sol-gel derived PbTiO3 (PT) thin films. The structure, morphology and electrical properties of the multilayer films were characterized by some analytical techniques and electrical measurements. PT film on LNO/Si had pure perovskite phase with sharp cross-section and small surface roughness. Most Raman modes of PT films shifted to the low frequency due to the pressure effect in the films. PT capacitor showed saturated hysteresis loop, higher resistivity and breakdown voltage. These results indicated the PT/LNO/Si heterostructure fabricated by sol-gel and MOD techniques to be a promising combination for microelectronic device.

Li Aidong;Wu Di;Ge Chuanzhen;Wang Mu;Liu Zhiguo;Ming Naiben;Wang Hong;Wang Min

Thin Solid Films

2000

Both the strength of an applied biased electrical field and the substrate temperature were found to have significant effect on the oriented growth of LiNbO3 thin films prepared by pulsed laser deposition technique. At a substrate temperature of 600 °C and an applied electrical field of 7 V/cm, completely (001) oriented LiNbO3 films were deposited on silica and other amorphous substrates successfully. The physical background of the oriented growth of ferroelectrical films induced by low electric field was analyzed in terms of nucleation and growth theory of ferroelectrics with spontaneous polarization in electrical field and the deposition temperature effect on the intensity of spontaneous polarization of the ferroelectrics.

Wu Zhuang-Chun;Hu Wei-Sheng;Liu Jun-Ming;Wang Mu;Liu Zhi-Guo

Wuli Xuebao Acta Physica Sinica

1998

The random copolymers of styrene (St) and 4-vinylpyridine (4-VP) with hydroxyl end group and low polydispersities were synthesized by nitroxide-mediated living radical polymerization initiated by azobisisobutyronitrile (AIBN) and 4-hydroxyl-2,2,6,6-tetramethylpiperidineoxyl (TEMPO-OH). The experimental results have shown that all synthesized copolymers have narrow molecular weight distribution. The conversion of monomers and the molecular weight of copolymer increased with polymerization time. The copolymerization rate is affected by molar ratios of HTEMPO to AIBN. ¹ H-Nuclear magnetic resonance spectra shows that one end of copolymers was capped by TEMPO-OH moiety. The use of this method permits the copolymer with hydroxyl chain end and controllable molecular weight and molecular weight distribution.

Chen Zhijun;Wang Yuan;Jiang Xiqun;Yang Changzheng;Feng Yan;Wang Mu

Journal of Applied Polymer Science

2004

In the frame of the tight-binding approximation, we study the electronic transport and delocalization in one-dimensional random-polymer chains, where the impurity clusters are randomly distributed in the host monatomic chain and the impurity atoms possess inverse symmetry in each cluster. As an example, the asymmetric trimer case is presented first. The resonant energy is obtained analytically, which has been demonstrated by the numerical calculation on the electronic transmission. According to the zero Lyapunov exponent at the resonant energy, we confirm that electronic delocalization, indeed, exists in the model. Moreover, the undecayed electronic wave functions are shown near the resonant energy. Thereafter, we generalize the asymmetric trimer model to a polymer one with inversely symmetric impurities. The electronic delocalization and resonant scattering have been found in this generalized polymer model. The result is beyond the common viewpoint that the internal mirror symmetry in the defects is the necessary condition for the presence of delocaliztion in such correlated systems. The polymer model presented here may provide a way to make different types of polymers with high electronic conductivity. © 2003 The American Physical Society.

Liu Y. M.;Peng R. W.;Huang X. Q.;Wang Mu;Hu A.;Jiang S. S.

Physical Review B Condensed Matter and Materials Physics

2003

Ultrathin La 2 O 3 gate dielectric films were prepared on Si substrate using La(tmhd) 3 source by low pressure metalorganic chemical vapor deposition (MOCVD). The growth processing, interfacial structure and electrical properties have been investigated by various techniques. The ultrathin films deposited at 600 show amorphous structure with smaller roughness of ∼0.2nm and larger band gap of E g =6.18eV. This is attributed to the interfacial layer existence of compositionally graded La-Si-O silicate. Due to the chemical instability of La 2 O 3 films in ambient, it can absorb vapor and carbon dioxide, which leads to the deterioration of electrical properties. By introducing Al 2 O 3 capping layer, the reliable value of equivalent oxide thickness around 1.8nm of La 2 O 3 /Si has been achieved. © 2004 Elsevier B.V. All rights reserved.

Li Ai-Dong;Shao Qi-Yue;Wu Di;Wang Yuan;Bao Yong-Jun;Wang Mu;Liu Zhi-Guo;Ming Nai-Ben;Cheng Jin-Bo;Ling Hui-Qin

Applied Surface Science

2004

Multilayer structure YBa2Cu3O7 - δ (YBCO)/LaNiO3 (LNO)/SrTiO3 (STO)/MgO has been carefully studied in the hope that it can be used for applications such as quasiparticle injection or Josephson junction fabrication. Deposited by pulsed laser, LNO on STO-buffered (100) MgO has low resistivity, good metallic characteristics, and very smooth surface (with a mean-square-root roughness of less than 3 nm). After the deposition of LNO, YBCO film can be grown in situ on it, showing good superconducting properties with a critical temperature above 81 K and a narrow transition width below 1.5 K. X-ray diffraction analyses have indicated that all the deposited films are highly c-axis-oriented. © 2004 Elsevier B.V. All rights reserved.

Sun Guo-Zhu;Wu Pei-Heng;Ji Zheng-Ming;Yang Sen-Zu;Xu Wei-Wei;Kang Lin;Feng Yan;Wang Mu

Thin Solid Films

2005

We investigate the propagation of electromagnetic wave through dielectric heterostructures with transfer-matrix method. It is shown that if a dimerlike positional correlation (DPC) is introduced to the heterostructure, resonant transmission of light waves will definitely take place. The resonant transmissions are characterized by perfect transmission peaks in the photonic band gap, which is demonstrated by the electric-field distribution at corresponding resonant modes. The numerical calculations are in good agreement with the analytical predictions. Furthermore, by applying the Si O2 Si heterostructure with DPC, resonant modes can appear within the photonic band gap at the telecommunication wavelengths of 1.55 and 1.3 μm. This finding is expected to have potential applications in wavelength division multiplexing system. © 2005 American Institute of Physics.

Lu Ye;Peng R. W.;Wang Z.;Tang Z. H.;Huang X. Q.;Wang Mu;Qiu Y.;Hu A.;Jiang S. S.;Feng D.

Journal of Applied Physics

2005

LaAlO 3 (LAO) is explored in this work to replace SiO 2 as the gate dielectric material in metal-oxide-semiconductor field effect transistor. Amorphous LAO gate dielectric films were deposited on Si (0 0 1) substrates by low pressure metalorganic chemical vapor deposition using La(dpm) 3 and Al(acac) 3 sources. The effect of processing parameters such as deposition temperature and precursor vapor flux on growth, structure, morphology, and composition of LAO films has been investigated by various analytical methods deeply. The film growth mechanism on Si is reaction limiting instead of mass transport control. The reaction is thermally activated with activation energy of ∼37 kJ/mol. In the initial growth stage, Al element is deficient due to higher nucleation barrier on Si. The LAO films show a smooth surface and good thermal stability and remain amorphous up to a high temperature of 850 °C. The electrical properties of amorphous LAO ultrathin films on Si have also been evaluated, indicating LAO is suitable for high k gate dielectric applications. © 2004 Elsevier B.V. All rights reserved.

Shao Qi-Yue;Li Ai-Dong;Cheng Jin-Bo;Ling Hui-Qin;Wu Di;Liu Zhi-Guo;Bao Yong-Jun;Wang Mu;Ming Nai-Ben;Wang Cathy;Zhou Hong-Wei;Nguyen Bich-Yen

Applied Surface Science

2005

Thin films of relaxor ferroelectric Pb(Mg,Nb)O3-PbTiO 3 with different orientations were grown by pulsed-laser deposition on Si(100). By using (111)-, (110)- and (100)-oriented MgO thin film as buffer and the LaNiO3 thin film as a bottom electrode, (110)- and (100)- oriented or preferred and polycrystalline PMN-PT thin films were obtained. The (110)-oriented PMN-PT thin film showed dielectric permittivity of about 1350 and loss factor cosδ of <0.07. © Springer-Verlag 2004.

Chen X. Y.;Chen G. X.;Liu J. M.;Wang M.;Liu Z. G.;Wang J.;Wong K. H.;Mak C. L.

Applied Physics A Materials Science and Processing

2005

We report here a self-organized electroless deposition of copper in an ultrathin layer of CuS O4 electrolyte. Microscopically the branching rate of the copper deposits is significantly decreased, forming an array of smooth polycrystalline filaments. Compared with a conventional electrodeposition system, no macroscopic electric field is involved and the thickness of the electrolyte layer is greatly decreased. Therefore the electroless deposition takes place in a nearly ideal, two-dimensional diffusion-limited environment. We suggest that restriction of the thickness of the electrolyte film is responsible for the generation of smoother branches of the electrodeposits. Our data also show that even in a diffusion-limited scenario the aggregate morphology is not necessarily very ramified and fractal-like. © 2006 The American Physical Society.

Weng Yu-Yan;Si Jian-Wen;Gao Wen-Ting;Wu Zhe;Wang Mu;Peng Ru-Wen;Ming Nai-Ben

Physical Review E Statistical Nonlinear and Soft Matter Physics

2006