We investigated the effect of annealing process on microstructures and optical properties of the sol-gel derived Ba0.9Sr0.1TiO3 （BST） films. The BST films, fabricated by layer-by-layer high-temperature （≥ 650 ℃）...We investigated the effect of annealing process on microstructures and optical properties of the sol-gel derived Ba0.9Sr0.1TiO3 （BST） films. The BST films, fabricated by layer-by-layer high-temperature （≥ 650 ℃） annealing process, had laminated structures consisting of alternating dense and porous BST layers, and exhibited excellent optical performance as Bragg reflectors. The Bragg reflection characteristic can be enhanced with increasing annealing temperature. Those BST films fabricated at temperatures lower than 650 ℃ displayed uniform cross-sectional morphologies even treated at a higher temperature. The difference in the microstructures of the BST thin films was also discussed.展开更多
It is hard to simultaneously realize the high dielectric tunability and low loss for the single Ba_(0.6)Sr_(0.4)TiO_(3)(BST)dielectric film made through chemical method.Garnet structured Y_(2.80)Pr_(0.20)Fe_(5)O_(12)(...It is hard to simultaneously realize the high dielectric tunability and low loss for the single Ba_(0.6)Sr_(0.4)TiO_(3)(BST)dielectric film made through chemical method.Garnet structured Y_(2.80)Pr_(0.20)Fe_(5)O_(12)(YPrIG)ex-hibits the merits of high saturation magnetization and a much high resistivity,which are helpful for realizing magnetoelectric double tuning and suppressing the dielectric loss of BST film.In this work,Y_(2.80)Pr_(0.20)Fe_(5)O_(12)/Ba_(0.6)Sr_(0.4)TiO_(3)(YPrIG/BST)composite films were fabricated by sol-gel method.The com-posite films exhibited a low dielectric loss(0.0087),and got a magnetic tunability of 11.73%at 10 kOe and 1.44 MHz.Compared with BST film,the tunability of YPrIG/BST film was enhanced from 56.25%to 73.24%under the bias electric field of 800 kV/cm.Additionally,YPrIG/BST films exhibited an electromag-netic double adjustability.The electromagnetic tunability of YPrIG/BST composite films was as high as 80.40%at 1.44 MHz,under the DC bias electric field of 800 kV/cm and magnetic field of 10 kOe.This phenomenon can be explained in terms of the superposition effect of electric field and magnetic field.展开更多
BaxSr1-xTiO3 sol-gel thin films with x--0.5, 0.7 and 0.8 have been fabricated as AI/BST/Pt capacitor. The AC conductivity and dielectric properties over a frequency rang of 10 Hz and I MHz have been studied in order t...BaxSr1-xTiO3 sol-gel thin films with x--0.5, 0.7 and 0.8 have been fabricated as AI/BST/Pt capacitor. The AC conductivity and dielectric properties over a frequency rang of 10 Hz and I MHz have been studied in order to explore the ion dynamics and relaxation mechanisms in the films. The frequency dependent conductivity plots show three regions of conduction processes. Dielectric results show that ε＇ at low frequencies increases as Sr content decreases, whereas at high frequencies, it shows opposite variation, which is attributed to the dipole dynamics. The electric modulus plots reveal the relaxation peaks which are not observed in the ε＂ plots and the contribution of the grains, grain boundaries and electrode to the relaxation mechanisms.展开更多
Ba0.6Sr0.4TiO3 （BST） thin films with and without HfO 2 buffer layer were fabricated on Pt/Ti/SiO2/Si substrates by pulsed laser deposition. Dependences of HfO 2 thickness on the dielectric property and leakage curre...Ba0.6Sr0.4TiO3 （BST） thin films with and without HfO 2 buffer layer were fabricated on Pt/Ti/SiO2/Si substrates by pulsed laser deposition. Dependences of HfO 2 thickness on the dielectric property and leakage current of BST thin films were focused. The dielectric constant of BST thin films increased and then decreased with the increase of HfO 2 thickness, while the dielectric relaxation was gradually improved. The loss tangent and leakage current under positive bias decreased with the HfO 2 thickness increasing. The leakage current analysis based on the Schottky emission indicated an improvement of the BST/Pt interface with HfO 2 buffer layer. The loss tangent, tunability and figure of merit of optimized HfO 2 buffered BST thin film achieved 0.009 8, 21.91% （E max = 200 kV/cm）, 22.40 at 10 6 Hz, respectively.展开更多
Ferroelectric Ba0.65Sr0.35TiO3 （BST） thin films on the Pt/Ti/SiO2/Si substrate have been successfully prepared by sol-gel. Such films have approximately 300 nm thicknesses with a remnant polarization of about 2.95 ...Ferroelectric Ba0.65Sr0.35TiO3 （BST） thin films on the Pt/Ti/SiO2/Si substrate have been successfully prepared by sol-gel. Such films have approximately 300 nm thicknesses with a remnant polarization of about 2.95 μ℃/cm^2 and a coercive field of about 21.5 kV/cm. The investigations of X-ray diffraction and atomic force microscopy show that the BST films annealed at 650 ℃ exhibit a tetragonal structure and that the films dominantly consist of large column or grains of about 89 nm in diameter. The curves of the temperature dependence of dielectric coefficient in different frequencies display the curie transition at the temperature around 23 ℃. The dielectric loss tangent of BST thin fdms at 100 kHz is less than 0.04. As a result, the BST thin films are more applicable for fabrication of infrared detector compared with the BST thin films reported previously.展开更多
A new sol-gel process is applied to fabricate the BST （BaxSr1-xTiO3） sol and nano-powder of La-Mn-Al co-doping with Ba/Sr ratio 65/35, and the BST thick film is prepared in the Pt/Ti/SiO2/Si substrate. The powder an...A new sol-gel process is applied to fabricate the BST （BaxSr1-xTiO3） sol and nano-powder of La-Mn-Al co-doping with Ba/Sr ratio 65/35, and the BST thick film is prepared in the Pt/Ti/SiO2/Si substrate. The powder and thick film are characterized by X-ray diffraction and transmission electron microscope. The influence of La-Mn-Al co-doping on the dielectric properties and micro-structure of BST thick film is analyzed. The results show that the La, Mn, and Al ions can take an obvious restraint on the growth of BaSrTiO3 grains. The polycrystalline particles come into being during the crystallization of thick film, which may improve the uniformity and compactness of thick film. The influence of unequal-valence and doping amount on the leakage current, dielectric loss, and dielectric property are mainly discussed. The dielectric constant and dielectric loss of thick film are 1200 and 0.03, respectively, in the case of 1mol% La doping, 2mol% Mn doping, and 1mol% Al doping.展开更多
It was found that BST thin film was damaged by the irradiation of high density electron beam (the current density was about 2 nA/cm2). In-situ and real time EELS showed that the intensity ratio of Ti to O edge and the...It was found that BST thin film was damaged by the irradiation of high density electron beam (the current density was about 2 nA/cm2). In-situ and real time EELS showed that the intensity ratio of Ti to O edge and the distance between Ti and O edge changed. It indicated that the film lost oxygen and thus the oxidation states of positive ions lowered. EELS study with high spatial resolution proved that compared with the inner of columnar grains, the grain boundaries with special structure and chemical environment were the main passageway of oxygen loss.展开更多
High overtone bulk acoustic resonators(HBAR)are advantageous for on-chip quantum acoustodynamics(QAD)system as it gives access to stream of phonon modes with high lifetime in the microwave frequency range while retain...High overtone bulk acoustic resonators(HBAR)are advantageous for on-chip quantum acoustodynamics(QAD)system as it gives access to stream of phonon modes with high lifetime in the microwave frequency range while retaining low power consumption and microscale footprint.In this paper we present a HBAR based on barium strontium titanate(BST)thin-film mounted on sapphire with modes exhibiting frequency quality factor product(fQ)of 1.72×10^(15)Hz which is the highest reported for a bulk acoustic wave resonator utilizing polycrystalline ferroelectric material as a means for acoustic wave excitation.Unlike other piezoelectric based HBARs,the DC field-induced piezoelectricity utilized in this work offers multiple on-chip tuneability of resonator’s dynamic parameters such as phonon lifetime,frequency modulation and coupling.The higher overtone feature can enable qubit(s)in a hybrid quantum circuit to interact with one or more acoustic modes to form a quantum transducer.Here,the multi-mode resonator exhibits a unique DC bias dependency,and this feature of the ferroelectric thin film adds control variables that efficiently tune static and dynamic material,mechanical and electrical properties of the device.The resonator records a loaded quality factor of 180,000 in X band and 140,000 in the L band when measured at 10 K.A controllable robust resonator with simple fabrication technique offering high fQ can be a strong platform to be used in QAD circuits for applications in metrology,quantum memory and quantum information processing.展开更多
基金Funded by the National Natural Science Foundation of China(No.61106126)
文摘We investigated the effect of annealing process on microstructures and optical properties of the sol-gel derived Ba0.9Sr0.1TiO3 （BST） films. The BST films, fabricated by layer-by-layer high-temperature （≥ 650 ℃） annealing process, had laminated structures consisting of alternating dense and porous BST layers, and exhibited excellent optical performance as Bragg reflectors. The Bragg reflection characteristic can be enhanced with increasing annealing temperature. Those BST films fabricated at temperatures lower than 650 ℃ displayed uniform cross-sectional morphologies even treated at a higher temperature. The difference in the microstructures of the BST thin films was also discussed.
基金supported by the National Natural Science Foundation of China(Nos.52171191,52371198)Shaanxi Key Program for International Science and Technology Coopera-tion Projects(No.2021KWZ-12)the Youth Innovation Team of Shaanxi Universities.
文摘It is hard to simultaneously realize the high dielectric tunability and low loss for the single Ba_(0.6)Sr_(0.4)TiO_(3)(BST)dielectric film made through chemical method.Garnet structured Y_(2.80)Pr_(0.20)Fe_(5)O_(12)(YPrIG)ex-hibits the merits of high saturation magnetization and a much high resistivity,which are helpful for realizing magnetoelectric double tuning and suppressing the dielectric loss of BST film.In this work,Y_(2.80)Pr_(0.20)Fe_(5)O_(12)/Ba_(0.6)Sr_(0.4)TiO_(3)(YPrIG/BST)composite films were fabricated by sol-gel method.The com-posite films exhibited a low dielectric loss(0.0087),and got a magnetic tunability of 11.73%at 10 kOe and 1.44 MHz.Compared with BST film,the tunability of YPrIG/BST film was enhanced from 56.25%to 73.24%under the bias electric field of 800 kV/cm.Additionally,YPrIG/BST films exhibited an electromag-netic double adjustability.The electromagnetic tunability of YPrIG/BST composite films was as high as 80.40%at 1.44 MHz,under the DC bias electric field of 800 kV/cm and magnetic field of 10 kOe.This phenomenon can be explained in terms of the superposition effect of electric field and magnetic field.
文摘BaxSr1-xTiO3 sol-gel thin films with x--0.5, 0.7 and 0.8 have been fabricated as AI/BST/Pt capacitor. The AC conductivity and dielectric properties over a frequency rang of 10 Hz and I MHz have been studied in order to explore the ion dynamics and relaxation mechanisms in the films. The frequency dependent conductivity plots show three regions of conduction processes. Dielectric results show that ε＇ at low frequencies increases as Sr content decreases, whereas at high frequencies, it shows opposite variation, which is attributed to the dipole dynamics. The electric modulus plots reveal the relaxation peaks which are not observed in the ε＂ plots and the contribution of the grains, grain boundaries and electrode to the relaxation mechanisms.
基金Project supported by the Foundation of the Education Commission of Shanghai Municipality (Grant Nos.07ZZ14, 08SG41)the National Natural Science Foundation of China (Grant No.50711130241)the Shanghai Rising Star Program (GrantNo.08QH14008)
文摘Ba0.6Sr0.4TiO3 （BST） thin films with and without HfO 2 buffer layer were fabricated on Pt/Ti/SiO2/Si substrates by pulsed laser deposition. Dependences of HfO 2 thickness on the dielectric property and leakage current of BST thin films were focused. The dielectric constant of BST thin films increased and then decreased with the increase of HfO 2 thickness, while the dielectric relaxation was gradually improved. The loss tangent and leakage current under positive bias decreased with the HfO 2 thickness increasing. The leakage current analysis based on the Schottky emission indicated an improvement of the BST/Pt interface with HfO 2 buffer layer. The loss tangent, tunability and figure of merit of optimized HfO 2 buffered BST thin film achieved 0.009 8, 21.91% （E max = 200 kV/cm）, 22.40 at 10 6 Hz, respectively.
文摘Ferroelectric Ba0.65Sr0.35TiO3 （BST） thin films on the Pt/Ti/SiO2/Si substrate have been successfully prepared by sol-gel. Such films have approximately 300 nm thicknesses with a remnant polarization of about 2.95 μ℃/cm^2 and a coercive field of about 21.5 kV/cm. The investigations of X-ray diffraction and atomic force microscopy show that the BST films annealed at 650 ℃ exhibit a tetragonal structure and that the films dominantly consist of large column or grains of about 89 nm in diameter. The curves of the temperature dependence of dielectric coefficient in different frequencies display the curie transition at the temperature around 23 ℃. The dielectric loss tangent of BST thin fdms at 100 kHz is less than 0.04. As a result, the BST thin films are more applicable for fabrication of infrared detector compared with the BST thin films reported previously.
基金supported by the National High Technology Research and Development Program of China under Grant No2007AA032120the National Natural Science Foundation of China under Grant No 60777043
文摘A new sol-gel process is applied to fabricate the BST （BaxSr1-xTiO3） sol and nano-powder of La-Mn-Al co-doping with Ba/Sr ratio 65/35, and the BST thick film is prepared in the Pt/Ti/SiO2/Si substrate. The powder and thick film are characterized by X-ray diffraction and transmission electron microscope. The influence of La-Mn-Al co-doping on the dielectric properties and micro-structure of BST thick film is analyzed. The results show that the La, Mn, and Al ions can take an obvious restraint on the growth of BaSrTiO3 grains. The polycrystalline particles come into being during the crystallization of thick film, which may improve the uniformity and compactness of thick film. The influence of unequal-valence and doping amount on the leakage current, dielectric loss, and dielectric property are mainly discussed. The dielectric constant and dielectric loss of thick film are 1200 and 0.03, respectively, in the case of 1mol% La doping, 2mol% Mn doping, and 1mol% Al doping.
基金the National Natural Science Foundation of China (Grant No. 50172024) the National 973 Project, 985 Project of Tsinghua University.
文摘It was found that BST thin film was damaged by the irradiation of high density electron beam (the current density was about 2 nA/cm2). In-situ and real time EELS showed that the intensity ratio of Ti to O edge and the distance between Ti and O edge changed. It indicated that the film lost oxygen and thus the oxidation states of positive ions lowered. EELS study with high spatial resolution proved that compared with the inner of columnar grains, the grain boundaries with special structure and chemical environment were the main passageway of oxygen loss.
基金supported by the Indian Institute of Science(IISc)through the IoE PDF fellowship and the Department of Science&Technology(DST)under Grant No.DST/TDT/AM/2022/084the National Nanofabrication Centre(NNFC)for the fabrication facilityand the Micro Nano Characterisation Facility(MNCF)+2 种基金University of Hyderabad acknowledge the fund provided by DST-SERB(GrantNumber:CRG/2019/000427)MHRD(Grant Number:UoH-IoE F11/9/2019-U3(A))at the University of Hyderabadthe Abdul Kalam Technology Innovation National Fellowship(INAE/121/AKF/29)awarded to him.
文摘High overtone bulk acoustic resonators(HBAR)are advantageous for on-chip quantum acoustodynamics(QAD)system as it gives access to stream of phonon modes with high lifetime in the microwave frequency range while retaining low power consumption and microscale footprint.In this paper we present a HBAR based on barium strontium titanate(BST)thin-film mounted on sapphire with modes exhibiting frequency quality factor product(fQ)of 1.72×10^(15)Hz which is the highest reported for a bulk acoustic wave resonator utilizing polycrystalline ferroelectric material as a means for acoustic wave excitation.Unlike other piezoelectric based HBARs,the DC field-induced piezoelectricity utilized in this work offers multiple on-chip tuneability of resonator’s dynamic parameters such as phonon lifetime,frequency modulation and coupling.The higher overtone feature can enable qubit(s)in a hybrid quantum circuit to interact with one or more acoustic modes to form a quantum transducer.Here,the multi-mode resonator exhibits a unique DC bias dependency,and this feature of the ferroelectric thin film adds control variables that efficiently tune static and dynamic material,mechanical and electrical properties of the device.The resonator records a loaded quality factor of 180,000 in X band and 140,000 in the L band when measured at 10 K.A controllable robust resonator with simple fabrication technique offering high fQ can be a strong platform to be used in QAD circuits for applications in metrology,quantum memory and quantum information processing.
