Thin film capacitors with excellent energy storage performances,thermal stability and fatigue endurance are strongly desired in modern electrical and electronic industry.Herein,we design and prepare lead-free0.7Sr_(0....Thin film capacitors with excellent energy storage performances,thermal stability and fatigue endurance are strongly desired in modern electrical and electronic industry.Herein,we design and prepare lead-free0.7Sr_(0.7)Bi_(0.2)TiO_(3)-0.3BiFeO_(3)-x%Mn(x=0,0.5,1.5,2,3)thin films via sol-gel method.Mn ions of divalent valence combine with oxygen vacancies,forming defect complex,which results in marked decline in leakage current and obvious enhancement in breakdown strength.A high energy storage density~47.6 J cm^(-3)and good efficiency~65.68%are simultaneously achieved in 2%Mn doped 0.7Sr_(0.7)Bi_(0.2)TiO_(3)-0.3 BiFeO_(3)thin film capacitor.Moreover,the 2%Mn-doped thin film exhibits excellent thermal stability in wide operating temperature range(35–115℃)and strong fatigue endurance behaviors after 108 cycles.The above results demonstrate that 2%Mn-doped 0.7Sr_(0.7)Bi_(0.2)TiO_(3)-0.3 BiFeO_(3)thin film capacitor with superior energy storage performances is a potential candidate for electrostatic energy storage.展开更多
Properties of ferroelectric xBiInO3-(1-x)PbTiO3(xBI-(1-x)PT) thin films deposited on(101) SrRuO3/(200)Pt/(200) MgO substrates by rf magnetron sputtering method and effects of deposition conditions are inve...Properties of ferroelectric xBiInO3-(1-x)PbTiO3(xBI-(1-x)PT) thin films deposited on(101) SrRuO3/(200)Pt/(200) MgO substrates by rf magnetron sputtering method and effects of deposition conditions are investigated.The structures of the xBI-(1-x)PT films are characterized by x-ray diffraction and scanning electron microscopy.The results indicate that the thin films are grown with mainly(001) orientation. The chemical compositions of the films are analyzed by scanning electron probe and the results indicate that the loss phenomena of Pb and Bi elements depend on the pressure and temperature during the sputtering process.The sputtering parameters including target composition, substrate temperature, and gas pressure are adjusted to obtain optimum sputtering conditions. To decrease leakage currents,2 mol% La2 O3 is doped in the targets. The P-E hysteresis loops show that the optimized xBI-(1-x)PT(x = 0.24) film has high ferroelectricities with remnant polarization2 Pr = 80μC/cm2 and coercive electric field 2 EC = 300 kV/cm. The Curie temperature is about 640℃. The results show that the films have optimum performance and will have wide applications.展开更多
The effects of the modification of electrode/ceramic interfaces through a chemical solution deposition-derived PbO buffer layer on the fatigue endurance of lead zirconate titanate(PZT) thin films were investigated.T...The effects of the modification of electrode/ceramic interfaces through a chemical solution deposition-derived PbO buffer layer on the fatigue endurance of lead zirconate titanate(PZT) thin films were investigated.The grain size and the surface roughness of the PZT films increased through PbO interfacial modification.Moreover,the PZT films with PbO interfacial modification had a better crystallographic structure and no evident secondary phases were observed.While the remanent polarization and dielectric constant were reduced,the fatigue endurance was improved.Based on the results,the mechanism for the fatigue endurance improvement was discussed.展开更多
The 0.9Pb(Sc0.5Ta0.5)O3-0.1PbTiO3/0.55Pb(Sc0.5Ta0.5)O3-0.45 PbTiO3 multilayer thin films((PSTT10/45)n, n = 1-6, 10) are deposited on SiO2/Si(100) substrates by radio frequency magnetron sputtering technique ...The 0.9Pb(Sc0.5Ta0.5)O3-0.1PbTiO3/0.55Pb(Sc0.5Ta0.5)O3-0.45 PbTiO3 multilayer thin films((PSTT10/45)n, n = 1-6, 10) are deposited on SiO2/Si(100) substrates by radio frequency magnetron sputtering technique with La Ni O3 buffer and electrode layer, and the films are subsequently annealed by a two-step rapid thermal approach. It is found that the interfacial density of the film has an important influence on the electric property of the film. The electric property of the film increases and reaches its critical point with the increase of interface density, and then decreases with the further increase of the interface density. With an interfacial density of 16 μm-1, the film shows an optimized dielectric property(high dielectric constant, εr = 765, lowest dielectric loss, tan δ = 0.041, at 1 k Hz) and ferroelectric property(highest remnant polarization,2Pr = 36.9 μC/cm2, low coercive field, 2Ec = 71.9 k V/cm). The possible reason for the electric behavior of the film is the competition of the interface stress with the interface defect.展开更多
Helix unwinding in ferroelectric liquid crystals induced by an electric field is theoretically studied on the basis of the continuum theory. By applying a weak electric field tilted to the smectic layers, the contribu...Helix unwinding in ferroelectric liquid crystals induced by an electric field is theoretically studied on the basis of the continuum theory. By applying a weak electric field tilted to the smectic layers, the contribution of the dielectric interaction energy density to the total free energy density is increased. Approximation methods are used to calculate the free energy for different tilt angles between the electric field and the smectic layers. The obtained results suggest selecting the optimal number of pitches in the film that matches to the minimum of the free energy.展开更多
This paper discusses the possibility of synthesis of SBTL sol-gel films for use as active layers for non-volatile memory (FRAM). La-doped SrBi2Ta209 thin films were synthesized by sol-gel method on Pt/TiO2/BPSG/SiO2...This paper discusses the possibility of synthesis of SBTL sol-gel films for use as active layers for non-volatile memory (FRAM). La-doped SrBi2Ta209 thin films were synthesized by sol-gel method on Pt/TiO2/BPSG/SiO2/Si substrates. The structural features of the surface (AFM), crystallization behavior (XRD) during the heating and ferroelectric properties of synthesized films were discussed. It was shown that an optimum surface structure and a high share of perovskite phase of SBTL-films were compared to SBT-films (Theating=800 ℃). Achieved ferroelectric parameters suggested the possibility of using synthesized SBTL sol-gel films in non-volatile memory devices.展开更多
Bismuth ferrite(Bi_2Fe_4O_9) thin films were grown on p-type Si(100) substrate by radio-frequency magnetron sputtering at 873 K. X-ray diffraction, field emission scanning electron microscopy and Raman spectroscop...Bismuth ferrite(Bi_2Fe_4O_9) thin films were grown on p-type Si(100) substrate by radio-frequency magnetron sputtering at 873 K. X-ray diffraction, field emission scanning electron microscopy and Raman spectroscopy studies revealed that the grown films have single-phase polycrystalline nature and are crystallized in orthorhombic structure. The grain size of the grown thin films was found to increase(56–130 nm) with sputtering power. Atomic force microscopy images clearly illustrated that the grown thin films have smooth surface. Energy-dispersive X-ray analysis revealed the presence of Bi, Fe and O elements with desired ratio and also the absence of impurities in the grown films. Analysis of ferroelectric hysteresis loops revealed that the remanent polarization and coercive field increase with the increase in sputtering power. Vicker's hardness analysis showed that the hardness of films strongly depends on the grain size and film thickness, which are mainly determined by the sputtering power. The above observations revealed that Bi_2Fe_4O_9 thin film deposited at higher sputtering power has good crystallinity and shows better electrical properties.展开更多
基金the National Natural Science Foundation of China under Grant No.51332003 and 51372171。
文摘Thin film capacitors with excellent energy storage performances,thermal stability and fatigue endurance are strongly desired in modern electrical and electronic industry.Herein,we design and prepare lead-free0.7Sr_(0.7)Bi_(0.2)TiO_(3)-0.3BiFeO_(3)-x%Mn(x=0,0.5,1.5,2,3)thin films via sol-gel method.Mn ions of divalent valence combine with oxygen vacancies,forming defect complex,which results in marked decline in leakage current and obvious enhancement in breakdown strength.A high energy storage density~47.6 J cm^(-3)and good efficiency~65.68%are simultaneously achieved in 2%Mn doped 0.7Sr_(0.7)Bi_(0.2)TiO_(3)-0.3 BiFeO_(3)thin film capacitor.Moreover,the 2%Mn-doped thin film exhibits excellent thermal stability in wide operating temperature range(35–115℃)and strong fatigue endurance behaviors after 108 cycles.The above results demonstrate that 2%Mn-doped 0.7Sr_(0.7)Bi_(0.2)TiO_(3)-0.3 BiFeO_(3)thin film capacitor with superior energy storage performances is a potential candidate for electrostatic energy storage.
基金Supported by the National Natural Science Foundation of China under Grant No 11304160the Special Fund for Public Interest of China under Grant No 201510068,and the NUPTFC under Grant No NY215111
文摘Properties of ferroelectric xBiInO3-(1-x)PbTiO3(xBI-(1-x)PT) thin films deposited on(101) SrRuO3/(200)Pt/(200) MgO substrates by rf magnetron sputtering method and effects of deposition conditions are investigated.The structures of the xBI-(1-x)PT films are characterized by x-ray diffraction and scanning electron microscopy.The results indicate that the thin films are grown with mainly(001) orientation. The chemical compositions of the films are analyzed by scanning electron probe and the results indicate that the loss phenomena of Pb and Bi elements depend on the pressure and temperature during the sputtering process.The sputtering parameters including target composition, substrate temperature, and gas pressure are adjusted to obtain optimum sputtering conditions. To decrease leakage currents,2 mol% La2 O3 is doped in the targets. The P-E hysteresis loops show that the optimized xBI-(1-x)PT(x = 0.24) film has high ferroelectricities with remnant polarization2 Pr = 80μC/cm2 and coercive electric field 2 EC = 300 kV/cm. The Curie temperature is about 640℃. The results show that the films have optimum performance and will have wide applications.
基金support of Beijing Nova Program of China (2007B025)the National Natural Science Foundation of China (10979013)+1 种基金the Innovative Research Team in Universities (IRT 0509)the Major State Basic Research Development Program of China (No.2009CB623306)
文摘The effects of the modification of electrode/ceramic interfaces through a chemical solution deposition-derived PbO buffer layer on the fatigue endurance of lead zirconate titanate(PZT) thin films were investigated.The grain size and the surface roughness of the PZT films increased through PbO interfacial modification.Moreover,the PZT films with PbO interfacial modification had a better crystallographic structure and no evident secondary phases were observed.While the remanent polarization and dielectric constant were reduced,the fatigue endurance was improved.Based on the results,the mechanism for the fatigue endurance improvement was discussed.
基金Project supported by the National Natural Science Foundation of China(Grant No.60771016)the Scientific Research Foundation of Mianyang Normal University,China(Grant No.QD2013A07)
文摘The 0.9Pb(Sc0.5Ta0.5)O3-0.1PbTiO3/0.55Pb(Sc0.5Ta0.5)O3-0.45 PbTiO3 multilayer thin films((PSTT10/45)n, n = 1-6, 10) are deposited on SiO2/Si(100) substrates by radio frequency magnetron sputtering technique with La Ni O3 buffer and electrode layer, and the films are subsequently annealed by a two-step rapid thermal approach. It is found that the interfacial density of the film has an important influence on the electric property of the film. The electric property of the film increases and reaches its critical point with the increase of interface density, and then decreases with the further increase of the interface density. With an interfacial density of 16 μm-1, the film shows an optimized dielectric property(high dielectric constant, εr = 765, lowest dielectric loss, tan δ = 0.041, at 1 k Hz) and ferroelectric property(highest remnant polarization,2Pr = 36.9 μC/cm2, low coercive field, 2Ec = 71.9 k V/cm). The possible reason for the electric behavior of the film is the competition of the interface stress with the interface defect.
基金supported by the National Natural Science Foundation of China (No. 50872080)Shanghai Special Foundation of Nanotechnology (No. 1052nm07300)+1 种基金Shanghai Education Development Foundation (No. 08SG41)Shanghai Leading Academic Disciplines (No. S30107)
基金Project supported by the Russian Foundation for Basic Research(RFBR)(Grant No.14-02-97026)
文摘Helix unwinding in ferroelectric liquid crystals induced by an electric field is theoretically studied on the basis of the continuum theory. By applying a weak electric field tilted to the smectic layers, the contribution of the dielectric interaction energy density to the total free energy density is increased. Approximation methods are used to calculate the free energy for different tilt angles between the electric field and the smectic layers. The obtained results suggest selecting the optimal number of pitches in the film that matches to the minimum of the free energy.
文摘This paper discusses the possibility of synthesis of SBTL sol-gel films for use as active layers for non-volatile memory (FRAM). La-doped SrBi2Ta209 thin films were synthesized by sol-gel method on Pt/TiO2/BPSG/SiO2/Si substrates. The structural features of the surface (AFM), crystallization behavior (XRD) during the heating and ferroelectric properties of synthesized films were discussed. It was shown that an optimum surface structure and a high share of perovskite phase of SBTL-films were compared to SBT-films (Theating=800 ℃). Achieved ferroelectric parameters suggested the possibility of using synthesized SBTL sol-gel films in non-volatile memory devices.
文摘Bismuth ferrite(Bi_2Fe_4O_9) thin films were grown on p-type Si(100) substrate by radio-frequency magnetron sputtering at 873 K. X-ray diffraction, field emission scanning electron microscopy and Raman spectroscopy studies revealed that the grown films have single-phase polycrystalline nature and are crystallized in orthorhombic structure. The grain size of the grown thin films was found to increase(56–130 nm) with sputtering power. Atomic force microscopy images clearly illustrated that the grown thin films have smooth surface. Energy-dispersive X-ray analysis revealed the presence of Bi, Fe and O elements with desired ratio and also the absence of impurities in the grown films. Analysis of ferroelectric hysteresis loops revealed that the remanent polarization and coercive field increase with the increase in sputtering power. Vicker's hardness analysis showed that the hardness of films strongly depends on the grain size and film thickness, which are mainly determined by the sputtering power. The above observations revealed that Bi_2Fe_4O_9 thin film deposited at higher sputtering power has good crystallinity and shows better electrical properties.