scholarly journals Phase Structure and Electrical Properties of Sm-Doped BiFe0.98Mn0.02O3 Thin Films

Nanomaterials ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 108
Author(s):  
Yangyang Wang ◽  
Zhaoyang Li ◽  
Zhibiao Ma ◽  
Lingxu Wang ◽  
Xiaodong Guo ◽  
...  
Keyword(s):  
Phase Composition ◽  
Dielectric Property ◽  
Oxygen Vacancy ◽  
Leakage Current ◽  
Leakage Current Density ◽  
Current Density ◽  
Indium Tin Oxide ◽  
Photoelectron Spectroscopy ◽  
X Ray ◽  
Ito Glass

Bi1−xSmxFe0.98Mn0.02O3 (x = 0, 0.02, 0.04, 0.06; named BSFMx) (BSFM) films were prepared by the sol-gel method on indium tin oxide (ITO)/glass substrate. The effects of different Sm content on the crystal structure, phase composition, oxygen vacancy content, ferroelectric property, dielectric property, leakage property, leakage mechanism, and aging property of the BSFM films were systematically analyzed. X-ray diffraction (XRD) and Raman spectral analyses revealed that the sample had both R3c and Pnma phases. Through additional XRD fitting of the films, the content of the two phases of the sample was analyzed in detail, and it was found that the Pnma phase in the BSFMx = 0 film had the lowest abundance. X-ray photoelectron spectroscopy (XPS) analysis showed that the BSFMx = 0.04 film had the lowest oxygen vacancy content, which was conducive to a decrease in leakage current density and an improvement in dielectric properties. The diffraction peak of (110) exhibited the maximum intensity when the doping amount was 4 mol%, and the minimum leakage current density and a large remanent polarization intensity were also observed at room temperature (2Pr = 91.859 μC/cm2). By doping Sm at an appropriate amount, the leakage property of the BSFM films was reduced, the dielectric property was improved, and the aging process was delayed. The performance changes in the BSFM films were further explained from different perspectives, such as phase composition and oxygen vacancy content.

scholarly journals Significantly reduced leakage current density in Mn-doped BiFeO3 thin films deposited using spin coating technique

2021 ◽  
Vol 2070 (1) ◽  
pp. 012088
Author(s):  
Waseem Ahmad Wani ◽  
Nilofar Naaz ◽  
B. Harihara Venkataraman ◽  
Souvik Kundu ◽  
Kannan Ramaswamy
Keyword(s):  
Thin Films ◽  
Leakage Current ◽  
Leakage Current Density ◽  
Current Density ◽  
Indium Tin Oxide ◽  
Oxygen Vacancies ◽  
Oxide Glass ◽  
Mn Doping ◽  
X Ray ◽  
Mn Doped

Abstract BiFeO3 (BFO) and Mn-doped BFO thin films are prepared on indium tin oxide/glass substrates using wet chemical deposition technique. The role of Mn defects (3% to 10%) on the leakage current density and other physical properties of BFO thin film devices is investigated. The X-ray diffraction patterns confirm the single-phase formation of rhombohedrally distorted BFO thin films. The scanning electron microscopy images approve uniform and crack-free film depositions, which is of great importance to the practical device applications of such materials. The oxidation states are determined by X-ray photoelectron spectroscopy (XPS). These XPS results reveal the presence of multiple valence states of Fe ions (Fe2+, Fe3+) and Mn (Mn3+, Mn4+) ions, which play a decisive role in determining the leakage current density. However, the Mn-doping at the Fe site in BFO reduces oxygen vacancies and Fe2+ states, hence suppressing the leakage current density. The leakage current density is reduced by three orders of magnitude (10−4 – 10−7) A/cm2, upon Mn-doping as clearly demonstrated by J-V characteristics. These results indicate that the primary contributors to the conduction in BFO based thin films are oxygen vacancies and the Fe2+ states in these devices.

Low Temperature Preparation of High-Quality Pb(Zr,Ti)O3 Films by Metal Organic Chemical Vapor Deposition with High Reproducibility

2001 ◽  
Vol 688 ◽  
Author(s):  
Hiroshi Funakubo ◽  
Kuniharu Nagashima ◽  
Masanori Aratani ◽  
Kouji Tokita ◽  
Takahiro Oikawa ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Leakage Current ◽  
Leakage Current Density ◽  
Current Density ◽  
Vapor Deposition ◽  
Deposition Temperature ◽  
Chemical Vapor ◽  
Process Window ◽  
High Quality ◽  
Low Temperature Preparation

AbstractPb(Zr,Ti)O3 (PZT) is one of the most promising materials for ferroelectric random access memory (FeRAM) application. Among the various preparation methods, metalorganic chemical vapor deposition (MOCVD) has been recognized as a most important one to realize high density FeRAM because of its potential of high-step-coverage and large-area-uniformity of the film quality.In the present study, pulsed-MOCVD was developed in which a mixture of the source gases was pulsed introduced into reaction chamber with interval. By using this deposition technique, simultaneous improvements of the crystallinity, surface smoothness, and electrical property of the film have been reached by comparing to the conventional continuous gas-supplied MOCVD. Moreover, this film had larger remanent polarization (Pr) and lower leakage current density. This is owing to reevaporation of excess Pb element from the film and increase of migration on the surface of substrate during the interval time.This process is also very effective to decrease the deposition temperature of the film having high quality. In fact, the Pr and the leakage current density of polycrystalline Pb(Zr0.35Ti0.65)O3 film deposited at 415 °C were 41.4 μC/cm2 and on the order of 10−7 A/cm2 at 200 kV/cm. This Pr value was almost the same as that of the epitaxially grown film deposited at 415 °C with the same composition corrected for the orientation difference. This suggests that the polycrystalline PZT film prepared by pulsed-MOCVD had the epitaxial-grade ferroelectric properties even through the deposition temperature was as low as 415 °C. Moreover, large “process window” comparable to the process window at 580 °C, above 150 °C higher temperature and was widely used condition, was achieved even at 395°C by the optimization of the deposition condition.

scholarly journals Organosilane-functionalization of nanostructured indium tin oxide films

2016 ◽  
Vol 6 (6) ◽  
pp. 20160056 ◽  
Author(s):  
R. Pruna ◽  
F. Palacio ◽  
M. Martínez ◽  
O. Blázquez ◽  
S. Hernández ◽  
...  
Keyword(s):  
Surface Area ◽  
Indium Tin Oxide ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Annealing Treatment ◽  
Electrochemical Analysis ◽  
Cyclic Voltammograms ◽  
X Ray ◽  
Chip Technology ◽  
Significant Difference

Fabrication and organosilane-functionalization and characterization of nanostructured ITO electrodes are reported. Nanostructured ITO electrodes were obtained by electron beam evaporation, and a subsequent annealing treatment was selectively performed to modify their crystalline state. An increase in geometrical surface area in comparison with thin-film electrodes area was observed by atomic force microscopy, implying higher electroactive surface area for nanostructured ITO electrodes and thus higher detection levels. To investigate the increase in detectability, chemical organosilane-functionalization of nanostructured ITO electrodes was performed. The formation of 3-glycidoxypropyltrimethoxysilane (GOPTS) layers was detected by X-ray photoelectron spectroscopy. As an indirect method to confirm the presence of organosilane molecules on the ITO substrates, cyclic voltammetry and electrochemical impedance spectroscopy (EIS) were also carried out. Cyclic voltammograms of functionalized ITO electrodes presented lower reduction-oxidation peak currents compared with non-functionalized ITO electrodes. These results demonstrate the presence of the epoxysilane coating on the ITO surface. EIS showed that organosilane-functionalized electrodes present higher polarization resistance, acting as an electronic barrier for the electron transfer between the conductive solution and the ITO electrode. The results of these electrochemical measurements, together with the significant difference in the X-ray spectra between bare ITO and organosilane-functionalized ITO substrates, may point to a new exploitable oxide-based nanostructured material for biosensing applications. As a first step towards sensing, rapid functionalization of such substrates and their application to electrochemical analysis is tested in this work. Interestingly, oxide-based materials are highly integrable with the silicon chip technology, which would permit the easy adaptation of such sensors into lab-on-a-chip configurations, providing benefits such as reduced size and weight to facilitate on-chip integration, and leading to low-cost mass production of microanalysis systems.

Fabrication of the ZnS-ZnO Composite Film by Sulfurizing the as-Electrodeposited ZnO Film

2014 ◽  
Vol 881-883 ◽  
pp. 909-913
Author(s):  
Zi Feng Wang ◽  
Yong Zhao Liu ◽  
Yu Shan Liu ◽  
Jian Min Zhang
Keyword(s):  
Composite Film ◽  
Indium Tin Oxide ◽  
Zinc Nitrate ◽  
Hexagonal Structure ◽  
X Ray Diffraction ◽  
Zno Film ◽  
X Ray ◽  
Ito Glass ◽  
Sodium Sulfide Solution ◽  
Sulfide Solution

The ZnS-ZnO composite film was successfully prepared by sulfidation of the as-electrodeposited ZnO film in the aqueous solution of zinc nitrate and hexamethylenetetramine. The ZnO film was electrodeposited on the substrate of indium-tin oxide (ITO) glass, and then the sodium sulfide solution was used to convert the ZnO film into the ZnS-ZnO composite film. The products were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectrometer (EDS) and UVvisible absorption. The experimental results show that the composite film on ITO glass still retained the morphology of as-electrodeposited ZnO coating, and is composed of ZnS with cubic structure and ZnO with hexagonal structure.

3 kV Normally-Off 4H-SiC Buried Gate Static Induction Transistors (SiC-BGSITs)

2014 ◽  
Vol 778-780 ◽  
pp. 899-902 ◽  
Author(s):  
Akio Takatsuka ◽  
Yasunori Tanaka ◽  
Koji Yano ◽  
Norio Matsumoto ◽  
Tsutomu Yatsuo ◽  
...  
Keyword(s):  
Leakage Current ◽  
Leakage Current Density ◽  
Current Density ◽  
Threshold Voltage ◽  
Room Temperature ◽  
Fabrication Process ◽  
Drain Voltage ◽  
Static Induction Transistors ◽  
Static Induction

3 kV normally-off SiC-buried gate static induction transistors (SiC-BGSITs) were fabricated by using an innovative fabrication process that was used by us previously to fabricate 0.7–1.2 kV SiC-BGSITs. The fabricated device shows the lowest specific on-resistance of 9.16 mΩ·cm2, compared to all other devices of the same class. The threshold voltage of this device was 1.4 V at room temperature and was maintained at values more than 1 V with normally-off characteristics at 200 °C. The device can block drain voltage of 3 kV with a leakage current density of 6.9 mA/cm2.

Growth of Epitaxial Site-Engineered Bi4Ti3O12-Basded Thin Films by Mocvdand Their Characterization

2002 ◽  
Vol 748 ◽  
Author(s):  
Hiroshi Funakubo ◽  
Tomohiro Sakai ◽  
Takayuki Watanabe ◽  
Minoru Osada ◽  
Masato Kakihana ◽  
...  
Keyword(s):  
Thin Films ◽  
Leakage Current ◽  
Leakage Current Density ◽  
Current Density ◽  
Spontaneous Polarization ◽  
Chemical Vapor ◽  
The Other ◽  
Other Hand ◽  
La Substitution ◽  
Lower Temperature

ABSTRACTThin films of BIT, La-substituted BIT (BLT) and La- and V-cosubstituted BIT(BLTV) were epitaxially grown on SrRuO3//SrTiO3 substrates at 850°C by metalorganic chemical vapor deposition (MOCVD), and their electrical properties were systematically compared. All films on (100), (110) and (111)-oriented substrates were epitaxially grown with (001)-, (104)-/(014)-and (118) –preferred orientations, respectively. The leakage current density of the BLTV film was almost the same with that of the BLT film, but was smaller than that of BIT film, suggesting that the La substitution contributed to the decrease of the leakage current density especially in pseudoperovskite layer. Spontaneous polarization of the BLTV film was estimated to be almost the same with the BLT film but was smaller that that of the BIT film. This is explained by the decrease of Tc with the La substitution, while V did not contribute to the change of the Curie temperature (Tc ). On the other hand, the coercive field (Ec) value of the BLTV was smaller than that of the BIT and the BLT films. As a result, La substitution contributed to the decrease of the leakage current density together with the decrease of the spontaneous polarization due to the decrease of the Tc. On the other hand, V substitution contributes to the decrease of the defects that suppress the domain motion and increases the Ec value. Therefore, each substitution of La and V plays different roles and this contribution is remarkable for the films deposited at lower temperature.

scholarly journals Suppression of Oxygen Vacancy Defects in sALD-ZnO Films Annealed in Different Conditions

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 3910
Author(s):  
Ming-Jie Zhao ◽  
Zhi-Tao Sun ◽  
Zhi-Xuan Zhang ◽  
Xin-Peng Geng ◽  
Wan-Yu Wu ◽  
...  
Keyword(s):  
Oxygen Vacancy ◽  
Carrier Concentration ◽  
Photoelectron Spectroscopy ◽  
Annealing Temperature ◽  
Atomic Layer ◽  
Zno Films ◽  
High Deposition Rate ◽  
Xps Spectra ◽  
Vacancy Defects ◽  
X Ray

Zinc oxide (ZnO) has drawn much attention due to its excellent optical and electrical properties. In this study, ZnO film was prepared by a high-deposition-rate spatial atomic layer deposition (ALD) and subjected to a post-annealing process to suppress the intrinsic defects and improve the crystallinity and film properties. The results show that the film thickness increases with annealing temperature owing to the increment of oxide layer caused by the suppression of oxygen vacancy defects as indicated by the X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) spectra. The film transmittance is seldom influenced by annealing. The refractive index increases with annealing temperature at 300–700 °C, possibly due to higher density and crystallinity of the film. The band gap decreases after annealing, which should be ascribed to the decrease in carrier concentration according to Burstein–Moss model. The carrier concentration decreases with increasing annealing temperature at 300–700 °C since the oxygen vacancy defects are suppressed, then it increases at 800 °C possibly due to the out-diffusion of oxygen atoms from the film. Meanwhile, the carrier mobility increases with temperature due to higher crystallinity and larger crystallite size. The film resistivity increases at 300–700 °C then decreases at 800 °C, which should be ascribed primarily to the variation of carrier concentration.

scholarly journals Evaluation of Solar-Driven Photocatalytic Activity of Thermal Treated TiO2 under Various Atmospheres

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 163 ◽  
Author(s):  
Reza Katal ◽  
Saeideh Kholghi Eshkalak ◽  
Saeid Masudy-panah ◽  
Mohammadreza Kosari ◽  
Mohsen Saeedikhani ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Thermal Treatment ◽  
Oxygen Vacancy ◽  
Photoelectron Spectroscopy ◽  
Significant Feature ◽  
Positive Role ◽  
Paramagnetic Resonance ◽  
X Ray ◽  
Treatment Conditions ◽  
Treated Sample

In this report, the photocatalytic activity of P25 has been explored and the influence of thermal treatment under various atmospheres (air, vacuum and hydrogen) were discussed. The samples’ characteristics were disclosed by means of various instruments including X-ray diffraction (XRD), Electron paramagnetic resonance (EPR), X-ray photoelectron spectroscopy (XPS) and UV–vis. This study also accentuates various states of the oxygen vacancy density formed inside the samples as well as the colour turning observed in treated P25 under various atmospheres. Produced coloured TiO2 samples were then exploited for their photocatalytic capability concerning photodegradation of methylene blue (MB) using air mass (AM) 1.5 G solar light irradiation. Our findings revealed that exceptional photocatalytic activity of P25 is related to the thermal treatment. Neither oxygen vacancy formation nor photocatalytic activity enhancement was observed in the air-treated sample. H2-treated samples have shown better photoactivity which even could be further improved by optimizing treatment conditions to achieve the advantages of the positive role of oxygen vacancy (O-vacancy at higher concentration than optimum acts as electron trapping sites). The chemical structure and stability of the samples were also studied. There was no sign of deteriorating of O2-vacancies inside the samples after 6 months. High stability of thermal treated samples in terms of both long and short-term time intervals is another significant feature of the produced photocatalyst.

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