The influence of lanthanum doping on the physical and electrical properties of BTV ferroelectric thin films

In this study, the ferroelectricity of as-deposited Bi_3.9La_0.1Ti_2.9V_0.1O₁₂ (BLTV), Bi_3.9Ti_2.9V_0.1O₁₂ (BTV), and Bi₄Ti₃O₁₂ (BIT) thin films was prepared and compared by rf magnetron sputtering technology. For the BLTV, BTV, and BIT thin films deposited on Pt/Ti/SiO₂/Si and SiO₂/Si substrate, the physical and electrical characteristics of lanthanum doped BTV (BLTV) were better than those of BIT and BTV thin films. Regarding the physical properties, the micro-structure of as-deposited BTV and BLTV thin films were obtained and compared by XRD patterns and SEM images. The BLTV and BTV thin films were also exhibited clear the ferroelectricity. The remanent polarization (P _r ) of as-deposited BLTV thin films was 11 μC/cm² as the measured frequency of 100 kHz. It was higher than those of BTV thin films. Finally, the polarization of BLTV thin film capacitor decreased by 9%, while that of the BTV decreased by 15% after the fatigue test with 10⁹ switching cycles.     

Physical and electrical characteristics of Ba(Zr0.1Ti0.9)O3 thin films under oxygen plasma treatment for applications in nonvolatile memory devices

In this study, the effects of oxygen gas plasma treatment on the surface of Ba(Zr_0.1Ti_0.9)O₃ (BZT) films are investigated. The influence of oxygen plasma treatment on the crystal structure is developed by X-ray diffraction patterns and on the electrical characteristics are measured by the Al/BZT/Pt capacitor (metal–dielectric–metal) structure. Experimental results show that the capacitance increases and the leakage current density decreases as the oxygen plasma is treated on the BZT films. These results clearly indicate that the electrical characteristics of BZT films have effectively improved by means of the oxygen plasma surface treatment process. PACS 77.84.-s; 81.15.Cd; 73.40.Qv; 77.22.Ej; 51.50.+v     

Temperature and frequency dependence of the ferroelectric characteristics of BaTiO<Subscript>3</Subscript> thin films for nonvolatile memory applications

Ferroelectric thin films of BaTiO₃ were successfully deposited on SiO₂/Si substrate under the optimal rf magnetron sputtering conditions, and their electrical and ferroelectric characteristics were discussed. The memory window, capacitance, threshold voltage and leakage current density of MFIS structure under different frequencies and temperatures were also reported. The variations of ferroelectric capacitance and threshold voltage would be attributed to the as-deposited BaTiO₃ films of MFIS structure as the temperature and frequency increased. Besides, the memory window, threshold voltage and leakage current density would be degraded from 4 V, 5 V and 8×10^-10 A/cm² to 2.5 V, 10 V and 5×10^-4 A/cm², respectively, as the temperature increased from 25 to 90 °C. PACS 77.84.-s; 81.15.Cd; 73.40.Qv; 51.50.+v; 67.80.Gb     

Large memory window in the vanadium doped Bi4Ti3O12 thin films

We report the enhancement of ferroelectric properties in vanadium-doped Bi₄Ti₃O₁₂ (BIT) thin films prepared by rf magnetron sputtering method for MFM and MFIS structures. The optimal sputtering parameters of the as-deposited Bi_3.9Ti_2.9V_0.08O₁₂ (BTV) ferroelectric films for different depositing times were obtained. Compared to the undoped BIT, vanadium doped BIT (BTV) showed better physical and electrical characteristics. The as-deposited BTV showed a remanent polarization (2P _r ) of 23 μC/cm², higher than the value of 16 μC/cm² for BIT, as the measured frequency was 100 kHz. For BTV thin films in the MFIS structure, the leakage current density and the memory window decreased, the change ratio of capacitance critically increased as the depositing time increased from 30 to 120 min. Regarding the measured physical properties, the micro-structure and thickness of as-deposited undoped and vanadium doped BIT thin films were obtained and compared by XRD patterns and SEM images.     

Syntheses and Crystal Structures of 4-Amino-3- （3-hyd roxyp ropyl）- 1H-1,2,4-triazole-5（4H）-thione and 6-（4-Biphenylyl）-3-（3-hydroxypropyl）-7H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazine

1INTRODUCTION It has been reported that3,6-disubstituted-7H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazines have a broad spec-trum of bioactivities,such as antimicrobial[1],antibac-terial,antifungal[2],anti-inflammatory[3],diuretic[4],an-thelmintic and analgesic[5].They can also be used as plant-growth regulating agents[6],photographic coup-lers,dyes for improved preservability and absorption characteristics,and inhibitors of malignant cellularZOU K.H.et al.:Syntheses and Crystal Structures o…     

Low temperature improvement method on characteristics of Ba(Zr0.1Ti0.9)O3 thin films deposited on indium tin oxide/glass substrates

To improve the electrical properties of as-deposited BZ1T9 ferroelectric thin films, the supercritical carbon dioxide fluid (SCF) process were used by a low temperature treatment. In this study, the BZ1T9 ferroelectric thin films were post-treated by SCF process which mixed with propyl alcohol and pure H₂O. After SCF process treatment, the remnant polarization increased in hysteresis curves, and the passivation of oxygen vacancy and defect in leakage current density curves were found. Additionally, the improvement qualities of as-deposited BZ1T9 thin films after SCF process treatment were carried out XPS, C–V, and J–E measurements.     

Electrical conduction and bipolar switching properties in transparent vanadium oxide resistive random access memory (RRAM) devices

In this study, the electrical conduction and bipolar switching properties in transparent vanadium oxide thin films are investigated and discussed. (110)-oriented vanadium oxide thin films were well deposited onto transparent ITO substrates for the possible development of applications in the structure of system-on-panel devices. For the as-deposited vanadium oxide thin films, they were prepared for 1 h by a rf magnetron sputtering method of rf power 130 W, chamber pressure 10 mTorr, substrate temperature 550 °C, and different oxygen concentrations. In addition, the Al/V₂O₅/ITO device presents reliable and bipolar switching behavior. The on/off ratio and switching cycling of two stable states are found and discussed. We suggest that the current–voltage characteristics are governed by ohmic contact and Poole?Frankel emission transport model mechanisms in low- and high-voltage regions, respectively.     

The influence of different fabrication processes on characteristics of excess Bi2O3-doped 0.95 (Na0.5Bi0.5)TiO3–0.05 BaTiO3 ceramics

In this study, we will develop the influences of the excess x wt% (x=0, 1, 2, and 3) Bi₂O₃-doped and the different fabricating process on the sintering and dielectric characteristics of 0.95 (Na_0.5Bi_0.5)TiO₃–0.05 BaTiO₃ ferroelectric ceramics with the aid of SEM and X-ray diffraction patterns, and dielectric–temperature curves. The 0.95 (Na_0.5Bi_0.5)TiO₃–0.05 BaTiO₃+x wt% Bi₂O₃ ceramics are fabricated by two different processes. The first process is that (Na_0.5Bi_0.5)TiO₃ composition is calcined at 850 °C and BaTiO₃ composition is calcined at 1100 °C, then the calcined (Na_0.5Bi_0.5)TiO₃ and BaTiO₃ powders are mixed in according to 0.95 (Na_0.5Bi_0.5)TiO₃–0.05 BaTiO₃+x wt% Bi₂O₃ compositions. The second process is that the raw materials are mixed in accordance to the 0.95 (Na_0.5Bi_0.5)TiO₃–0.05 BaTiO₃+x wt% Bi₂O₃ compositions and then calcining at 900 °C. The sintering process is carried out in air for 2 h from 1120 to 1240 °C. After sintering, the effects of process parameters on the dielectric characteristics will be developed by the dielectric–temperature curves. Dielectric–temperature properties are also investigated at the temperatures of 30–350 °C and at the frequencies of 10 kHz–1 MHz.