In an attempt of being used as buffer layers and electrodes for the textured BaTiO3 （BTO） ferroelectric thin films, highly （100）-oriented LaNiO3 （LNO） thin films of different thicknesses were deposited directly ...In an attempt of being used as buffer layers and electrodes for the textured BaTiO3 （BTO） ferroelectric thin films, highly （100）-oriented LaNiO3 （LNO） thin films of different thicknesses were deposited directly on Si （100） substrate with radio-frequency （RF） magnetron sputtering method. It is observed that the substrate temperatures and the film thicknesses bring main influences on the microstructures and orientation of the thin film. The effects of the thicknesses and substrate temperatures on the orientation of the films were studied on the LNO films of different thicknesses. The highly （100）-oriented LNO thin films were obtained at the substrate temperature of 600℃. The existence of epitaxially grown BTO films indicates that the oriented LNO thin films obtained in this work could be used as a buffer layer for epitaxial growth.展开更多
LaNiO3 (LNO) thin films were prepared on Pt(111) / Ti / SiO2 / Si substrate by metal-organic decomposition (MOD) method. Pb(Zr,Ti)O3 ferroelectric thin films and their compositionally graded thin films were prepared o...LaNiO3 (LNO) thin films were prepared on Pt(111) / Ti / SiO2 / Si substrate by metal-organic decomposition (MOD) method. Pb(Zr,Ti)O3 ferroelectric thin films and their compositionally graded thin films were prepared on LNO / Pt / Ti / SiO2 /Si substrates by Sol-gel method. The composition depth profile of a typical up-graded film was determined by using a combination of Auger Electron Spectroscopy (ASE) and Ar Ion Etching. The results confirm that the processing method produces graded composition changes. XRD analysis showed that the graded thin films possessed composite structure of tetragonal and rhombohedral. The dielectric constants of Up-graded and Down-graded thin films were higher than that of each thin film unit. The dielectric constants were 277 and 269 at 10 kHz, respectively. The loss tangents were 0.019 and 0.018 at 10 kHz, respectively. The Hysteresis loops showed that the remanent polarizations of graded thin films were higher than that of each thin film unit, but the coercive fields were smaller. The remanent polarizations of Up-graded and Down-graded thin films were 30.06 and 26.96 μC·cm-2, respectively. The coercive fields were 54.14, 54.23 kV·cm-1, respectively. The pyroelectric coefficients of Up-graded and Down-graded thin films were 4.62, 2.51×10-8 C·cm-2·K-1 at room temperature, respectively. They were higher than that of each thin film unit.展开更多
LaNiO3 thin films with different La/Ni ratios were deposited on Si substrates by sol-gel process. The electrical resistivities of LaNixO3＋δfilms with different La/Ni ratios were measured by four-probe method.LaNi（0...LaNiO3 thin films with different La/Ni ratios were deposited on Si substrates by sol-gel process. The electrical resistivities of LaNixO3＋δfilms with different La/Ni ratios were measured by four-probe method.LaNi（0.95）O3＋δthin film has the lowest resistivity. First-principle calculations show that LaNi（0.95）O3＋δhas the largest Ni-O-Ni bond angle and the shortest Ni-O bond length, which means LaNi（0.95）O3＋δhas the strongest metallic property, hence, the electrical resistivity is the lowest. Au/PZT（PbZr（0.52）Ti（0.48）O3）/LaNixO3＋δand Au/PZT/Pt ferroelectric capacitors were fabricated to evaluate LaNixO3＋δas a bottom electrode. It is shown that fatigue properties of PZT films can be significantly improved by using LaNixO3＋δinstead of Pt as the bottom electrode. The Ⅰ-Ⅴ test results of PZT films show that LaNi（0.95）O3＋δas bottom electrode can reduce the threshold voltages of PZT films, suggesting that La/Ni ratio in LaNixO3＋δas a large influence on the film properties.展开更多
文摘In an attempt of being used as buffer layers and electrodes for the textured BaTiO3 （BTO） ferroelectric thin films, highly （100）-oriented LaNiO3 （LNO） thin films of different thicknesses were deposited directly on Si （100） substrate with radio-frequency （RF） magnetron sputtering method. It is observed that the substrate temperatures and the film thicknesses bring main influences on the microstructures and orientation of the thin film. The effects of the thicknesses and substrate temperatures on the orientation of the films were studied on the LNO films of different thicknesses. The highly （100）-oriented LNO thin films were obtained at the substrate temperature of 600℃. The existence of epitaxially grown BTO films indicates that the oriented LNO thin films obtained in this work could be used as a buffer layer for epitaxial growth.
文摘LaNiO3 (LNO) thin films were prepared on Pt(111) / Ti / SiO2 / Si substrate by metal-organic decomposition (MOD) method. Pb(Zr,Ti)O3 ferroelectric thin films and their compositionally graded thin films were prepared on LNO / Pt / Ti / SiO2 /Si substrates by Sol-gel method. The composition depth profile of a typical up-graded film was determined by using a combination of Auger Electron Spectroscopy (ASE) and Ar Ion Etching. The results confirm that the processing method produces graded composition changes. XRD analysis showed that the graded thin films possessed composite structure of tetragonal and rhombohedral. The dielectric constants of Up-graded and Down-graded thin films were higher than that of each thin film unit. The dielectric constants were 277 and 269 at 10 kHz, respectively. The loss tangents were 0.019 and 0.018 at 10 kHz, respectively. The Hysteresis loops showed that the remanent polarizations of graded thin films were higher than that of each thin film unit, but the coercive fields were smaller. The remanent polarizations of Up-graded and Down-graded thin films were 30.06 and 26.96 μC·cm-2, respectively. The coercive fields were 54.14, 54.23 kV·cm-1, respectively. The pyroelectric coefficients of Up-graded and Down-graded thin films were 4.62, 2.51×10-8 C·cm-2·K-1 at room temperature, respectively. They were higher than that of each thin film unit.
基金support from the Key Laboratory of Advanced Ceramics and Machining Technology, Ministry of Education (Tianjin University)
文摘LaNiO3 thin films with different La/Ni ratios were deposited on Si substrates by sol-gel process. The electrical resistivities of LaNixO3＋δfilms with different La/Ni ratios were measured by four-probe method.LaNi（0.95）O3＋δthin film has the lowest resistivity. First-principle calculations show that LaNi（0.95）O3＋δhas the largest Ni-O-Ni bond angle and the shortest Ni-O bond length, which means LaNi（0.95）O3＋δhas the strongest metallic property, hence, the electrical resistivity is the lowest. Au/PZT（PbZr（0.52）Ti（0.48）O3）/LaNixO3＋δand Au/PZT/Pt ferroelectric capacitors were fabricated to evaluate LaNixO3＋δas a bottom electrode. It is shown that fatigue properties of PZT films can be significantly improved by using LaNixO3＋δinstead of Pt as the bottom electrode. The Ⅰ-Ⅴ test results of PZT films show that LaNi（0.95）O3＋δas bottom electrode can reduce the threshold voltages of PZT films, suggesting that La/Ni ratio in LaNixO3＋δas a large influence on the film properties.
文摘通过MOD法在Si(100)和Pt(111)Ti SiO2Si基片上制备出LaNiO3(LNO)薄膜.再通过修正的Sol gel法,在Pt(111)Ti SiO2Si,LNO Si(100)和LNO Pt Ti SiO2Si三种衬底上制备出具有择优取向的Pb(Zr0.52Ti0.48)O3铁电薄膜.经XRD分析表明,LNO薄膜具有(100)择优取向的类钙钛矿结构;PZT薄膜均具有钙钛矿结构,且在Pt(111)Ti SiO2Si衬底上的薄膜以(110)择优取向,在LNO Pt Ti SiO2Si和LNO Si(100)衬底上的薄膜以(100)择优取向.经场发射SEM分析和介电、铁电性能测试表明,在LNO Si和LNO Pt Ti SiO2Si衬底上的PZT薄膜的平均粒径、介电常数以及剩余极化强度均比以Pt Ti SiO2Si为衬底的薄膜大.
