The Experts below are selected from a list of 270 Experts worldwide ranked by ideXlab platform
L. Sengupta - One of the best experts on this subject based on the ideXlab platform.
-
nonlinear response and power handling capability of Ferroelectric baxsr1 xtio3 Film capacitors and tunable microwave devices
Journal of Applied Physics, 2000Co-Authors: Alexander B. Kozyrev, T. B. Samoilova, O. I. Soldatenkov, Konstantin Astafiev, A Ivanov, L. SenguptaAbstract:The nonlinear response of Ferroelectric BaxSr1−xTiO3 Films to microwave electric field intensity up to ∼3×106 V/m was studied. Two techniques were used for this investigation: (i) 10 GHz pulsed power measurements, and (ii) 4 GHz intermodulation distortion (IMD) measurements. The nonlinear distortion of the resonant curve under microwave pulsed power and generation of the third-order IMD products in microwave resonators using Ferroelectric Film planar capacitors were measured. The use of microwave pulses and continuous signals enabled the separation of the nonlinear dielectric response from the heating response of the Ferroelectric Films and the microwave nonlinear parameters of the Ferroelectric Films to be determined. It is shown that up to a specified value of microwave voltage amplitude the nonlinear response of BaxSr1−xTiO3 Film capacitors can be predicted from the small signal capacitance–voltage characteristics. Formulas to estimate power handling capability connected with the field dielectric nonlinearity and the Film overheating are derived for the tunable microwave devices based on Ferroelectric Films.The nonlinear response of Ferroelectric BaxSr1−xTiO3 Films to microwave electric field intensity up to ∼3×106 V/m was studied. Two techniques were used for this investigation: (i) 10 GHz pulsed power measurements, and (ii) 4 GHz intermodulation distortion (IMD) measurements. The nonlinear distortion of the resonant curve under microwave pulsed power and generation of the third-order IMD products in microwave resonators using Ferroelectric Film planar capacitors were measured. The use of microwave pulses and continuous signals enabled the separation of the nonlinear dielectric response from the heating response of the Ferroelectric Films and the microwave nonlinear parameters of the Ferroelectric Films to be determined. It is shown that up to a specified value of microwave voltage amplitude the nonlinear response of BaxSr1−xTiO3 Film capacitors can be predicted from the small signal capacitance–voltage characteristics. Formulas to estimate power handling capability connected with the field dielectric nonli...
-
nonlinear response and power handling capability of Ferroelectric baxsr1 xtio3 Film capacitors and tunable microwave devices
Journal of Applied Physics, 2000Co-Authors: Alexander B. Kozyrev, T. B. Samoilova, O. I. Soldatenkov, Konstantin Astafiev, A Ivanov, L. SenguptaAbstract:The nonlinear response of Ferroelectric BaxSr1−xTiO3 Films to microwave electric field intensity up to ∼3×106 V/m was studied. Two techniques were used for this investigation: (i) 10 GHz pulsed power measurements, and (ii) 4 GHz intermodulation distortion (IMD) measurements. The nonlinear distortion of the resonant curve under microwave pulsed power and generation of the third-order IMD products in microwave resonators using Ferroelectric Film planar capacitors were measured. The use of microwave pulses and continuous signals enabled the separation of the nonlinear dielectric response from the heating response of the Ferroelectric Films and the microwave nonlinear parameters of the Ferroelectric Films to be determined. It is shown that up to a specified value of microwave voltage amplitude the nonlinear response of BaxSr1−xTiO3 Film capacitors can be predicted from the small signal capacitance–voltage characteristics. Formulas to estimate power handling capability connected with the field dielectric nonli...
P K Larsen - One of the best experts on this subject based on the ideXlab platform.
-
stresses in pt pb zr ti o3 pt thin Film stacks for integrated Ferroelectric capacitors
Journal of Applied Physics, 1995Co-Authors: G A C M Spierings, Guido J M Dormans, W G J Moors, M J E Ulenaers, P K LarsenAbstract:A study of the stresses in a Ferroelectric capacitor stack deposited on an oxidized silicon substrate is presented. The capacitor stack was prepared with sputtered Pt bottom and top electrodes and a Ferroelectric Film of composition PbZrxTi1−xO3 (PZT) with x≊0.5 which was deposited using a modified sol‐gel technique. The stresses were determined by the changes in the radius of curvature of the wafer following the deposition steps, during and after annealing treatments, and after etching steps in which the top electrode, the PZT Film, and the bottom electrode were successively removed. The largest stress effects are found in the Pt electrodes which are deposited under conditions giving an intrinsic compressive stress. An annealing treatment exceeding 500 °C changed the stress of the bottom electrode from ≊−750 MPa (compressive) to a large tensile stress (≊1 GPa). This stress is largely thermal and is caused by the differences in thermal‐expansion coefficients of the Pt Film and the Si substrate. The stress...
-
Ferroelectric properties and fatigue of pbzr0 51ti0 49o3 thin Films of varying thickness blocking layer model
Journal of Applied Physics, 1994Co-Authors: P K Larsen, Guido J M Dormans, D J Taylor, P J Van VeldhovenAbstract:Ferroelectric capacitors having Pt bottom and top electrodes and a Ferroelectric Film of composition PbZr0.51Ti0.49O3 (PZT) were fabricated and investigated. The PZT Films of thicknesses varying from 0.12 to 0.69 μm were prepared by organometallic chemical‐vapor deposition. Annealed capacitors were investigated by capacitance, hysteresis, and pulse switching measurements. It is found that the thickness dependence of the reciprocal capacitance, the coercive voltage, and the polarization measured by pulse switching can all be explained by a blocking layer model, in which a dielectric layer of thickness dbl and relative permittivity ebl is situated between the PZT Film and an electrode. It is shown that (i) the coercive field is independent of thickness having a value of 2.4 V/μm; (ii) the ratio ebl/dbl is in the range 20–28 nm−1; (iii) the voltage across the blocking layer is proportional to the polarization, Vbl=cP, where c=4.1±0.5 V m2/C; and (iv) the polarization depends on the electric field in the PZT ...
-
Ferroelectric properties and fatigue of pbzr0 51ti0 49o3 thin Films of varying thickness blocking layer model
Journal of Applied Physics, 1994Co-Authors: P K Larsen, Guido J M Dormans, D J Taylor, P J Van VeldhovenAbstract:Ferroelectric capacitors having Pt bottom and top electrodes and a Ferroelectric Film of composition PbZr0.51Ti0.49O3 (PZT) were fabricated and investigated. The PZT Films of thicknesses varying from 0.12 to 0.69 μm were prepared by organometallic chemical‐vapor deposition. Annealed capacitors were investigated by capacitance, hysteresis, and pulse switching measurements. It is found that the thickness dependence of the reciprocal capacitance, the coercive voltage, and the polarization measured by pulse switching can all be explained by a blocking layer model, in which a dielectric layer of thickness dbl and relative permittivity ebl is situated between the PZT Film and an electrode. It is shown that (i) the coercive field is independent of thickness having a value of 2.4 V/μm; (ii) the ratio ebl/dbl is in the range 20–28 nm−1; (iii) the voltage across the blocking layer is proportional to the polarization, Vbl=cP, where c=4.1±0.5 V m2/C; and (iv) the polarization depends on the electric field in the PZT layer, independent of thickness. Pulse switching endurance measurements showed that in the saturation range the fatigue for these Ferroelectric capacitors is determined by the pulse voltage and is independent of the thickness.
Alexander B. Kozyrev - One of the best experts on this subject based on the ideXlab platform.
-
nonlinear response and power handling capability of Ferroelectric baxsr1 xtio3 Film capacitors and tunable microwave devices
Journal of Applied Physics, 2000Co-Authors: Alexander B. Kozyrev, T. B. Samoilova, O. I. Soldatenkov, Konstantin Astafiev, A Ivanov, L. SenguptaAbstract:The nonlinear response of Ferroelectric BaxSr1−xTiO3 Films to microwave electric field intensity up to ∼3×106 V/m was studied. Two techniques were used for this investigation: (i) 10 GHz pulsed power measurements, and (ii) 4 GHz intermodulation distortion (IMD) measurements. The nonlinear distortion of the resonant curve under microwave pulsed power and generation of the third-order IMD products in microwave resonators using Ferroelectric Film planar capacitors were measured. The use of microwave pulses and continuous signals enabled the separation of the nonlinear dielectric response from the heating response of the Ferroelectric Films and the microwave nonlinear parameters of the Ferroelectric Films to be determined. It is shown that up to a specified value of microwave voltage amplitude the nonlinear response of BaxSr1−xTiO3 Film capacitors can be predicted from the small signal capacitance–voltage characteristics. Formulas to estimate power handling capability connected with the field dielectric nonlinearity and the Film overheating are derived for the tunable microwave devices based on Ferroelectric Films.The nonlinear response of Ferroelectric BaxSr1−xTiO3 Films to microwave electric field intensity up to ∼3×106 V/m was studied. Two techniques were used for this investigation: (i) 10 GHz pulsed power measurements, and (ii) 4 GHz intermodulation distortion (IMD) measurements. The nonlinear distortion of the resonant curve under microwave pulsed power and generation of the third-order IMD products in microwave resonators using Ferroelectric Film planar capacitors were measured. The use of microwave pulses and continuous signals enabled the separation of the nonlinear dielectric response from the heating response of the Ferroelectric Films and the microwave nonlinear parameters of the Ferroelectric Films to be determined. It is shown that up to a specified value of microwave voltage amplitude the nonlinear response of BaxSr1−xTiO3 Film capacitors can be predicted from the small signal capacitance–voltage characteristics. Formulas to estimate power handling capability connected with the field dielectric nonli...
-
nonlinear response and power handling capability of Ferroelectric baxsr1 xtio3 Film capacitors and tunable microwave devices
Journal of Applied Physics, 2000Co-Authors: Alexander B. Kozyrev, T. B. Samoilova, O. I. Soldatenkov, Konstantin Astafiev, A Ivanov, L. SenguptaAbstract:The nonlinear response of Ferroelectric BaxSr1−xTiO3 Films to microwave electric field intensity up to ∼3×106 V/m was studied. Two techniques were used for this investigation: (i) 10 GHz pulsed power measurements, and (ii) 4 GHz intermodulation distortion (IMD) measurements. The nonlinear distortion of the resonant curve under microwave pulsed power and generation of the third-order IMD products in microwave resonators using Ferroelectric Film planar capacitors were measured. The use of microwave pulses and continuous signals enabled the separation of the nonlinear dielectric response from the heating response of the Ferroelectric Films and the microwave nonlinear parameters of the Ferroelectric Films to be determined. It is shown that up to a specified value of microwave voltage amplitude the nonlinear response of BaxSr1−xTiO3 Film capacitors can be predicted from the small signal capacitance–voltage characteristics. Formulas to estimate power handling capability connected with the field dielectric nonli...
R Ramesh - One of the best experts on this subject based on the ideXlab platform.
-
negative capacitance in a Ferroelectric capacitor
arXiv: Mesoscale and Nanoscale Physics, 2014Co-Authors: Asif Islam Khan, Korok Chatterjee, Brian Wang, Steven Drapcho, Long You, Claudy Serrao, Saidur Rahman Bakaul, R Ramesh, Sayeef SalahuddinAbstract:The Boltzmann distribution of electrons poses a fundamental barrier to lowering energy dissipation in conventional electronics, often termed as Boltzmann Tyranny. Negative capacitance in Ferroelectric materials, which stems from the stored energy of phase transition, could provide a solution, but a direct measurement of negative capacitance has so far been elusive. Here we report the observation of negative capacitance in a thin, epitaxial Ferroelectric Film. When a voltage pulse is applied, the voltage across the Ferroelectric capacitor is found to be decreasing with time-in exactly the opposite direction to which voltage for a regular capacitor should change. Analysis of this inductance-like behavior from a capacitor presents an unprecedented insight into the intrinsic energy profile of the Ferroelectric material and could pave the way for completely new applications.
-
thickness dependence of structural and electrical properties in epitaxial lead zirconate titanate Films
Journal of Applied Physics, 1999Co-Authors: V Nagarajan, S Aggarwal, I G Jenkins, S P Alpay, L Salamancariba, Alexander L Roytburd, R RameshAbstract:We have studied the effect of misfit strain on the microstructure and properties of Ferroelectric lead zirconate titanate thin Films. We have changed the misfit strain by varying the Film thickness and studied the thickness effect on the domain formation of epitaxial PbZr0.2Ti0.8O3 (PZT) Films grown by pulsed laser deposition on (001) LaAlO3 substrates with La0.5Sr0.5CoO3 (LSCO) electrodes. The nominal thickness of the PZT Films was varied from 60 to 400 nm with the LSCO electrode thickness kept constant at 50 nm. X-ray diffraction experiments show that the Films relax via the formation of a domains, the fraction of which increase with the Ferroelectric Film thickness. The c-axis lattice constant of PZT Films calculated from the 002 reflection decreases with increasing Film thickness and approaches the bulk value of ∼0.413 nm in the Films thicker than 300 nm. Cross-sectional transmission electron microscopy images reveal that the a-domain fraction and period increase with increasing Film thickness. The re...
-
thickness dependence of structural and electrical properties in epitaxial lead zirconate titanate Films
Journal of Applied Physics, 1999Co-Authors: V Nagarajan, S Aggarwal, I G Jenkins, S P Alpay, L Salamancariba, Alexander L Roytburd, R RameshAbstract:We have studied the effect of misfit strain on the microstructure and properties of Ferroelectric lead zirconate titanate thin Films. We have changed the misfit strain by varying the Film thickness and studied the thickness effect on the domain formation of epitaxial PbZr0.2Ti0.8O3 (PZT) Films grown by pulsed laser deposition on (001) LaAlO3 substrates with La0.5Sr0.5CoO3 (LSCO) electrodes. The nominal thickness of the PZT Films was varied from 60 to 400 nm with the LSCO electrode thickness kept constant at 50 nm. X-ray diffraction experiments show that the Films relax via the formation of a domains, the fraction of which increase with the Ferroelectric Film thickness. The c-axis lattice constant of PZT Films calculated from the 002 reflection decreases with increasing Film thickness and approaches the bulk value of ∼0.413 nm in the Films thicker than 300 nm. Cross-sectional transmission electron microscopy images reveal that the a-domain fraction and period increase with increasing Film thickness. The relaxation of misfit strain in the Film is accompanied by systematic changes in the polarization properties, as well as the switching fields, quantified by the coercive field and the activation field.
Maksym V Strikha - One of the best experts on this subject based on the ideXlab platform.
-
integer quantum hall effect in graphene channel with p n junction at domain wall in a strained Ferroelectric Film
Journal of Applied Physics, 2019Co-Authors: Maksym V Strikha, Anatolii I Kurchak, Anna N MorozovskaAbstract:We revealed that 180° domain walls in a strained Ferroelectric Film can induce p-n junctions in a graphene channel and lead to the nontrivial temperature and gate voltage dependences of the perpendicular modes of the integer quantum Hall effect (IQHE). In particular, the number of perpendicular modes v⊥, corresponding to the p-n junction across the graphene channel, varies with the gate voltage increase from small integers to higher non-integer numbers, e.g., v⊥ = 1.9, 2, …, 5.1, 6.875, …, 9.1, …, 23,…, 37.4, in the vicinity of the transition temperature from the Ferroelectric to paraelectric phase. The non-integer numbers and their irregular sequence principally differ from the sequence of non-integer numbers ν = 3/2, 5/3, … reported earlier. The unusual v⊥-numbers originate from significantly different numbers of the edge modes, ν1 and ν2, corresponding to different concentrations of carriers in the left (n1) and right (n2) domains of the p-n junction boundary. The concentrations n1 and n2 are determined by the gate voltage and spontaneous polarization contributions, and so their difference originates from different directions of the spontaneous polarization in different domains of the strained Ferroelectric Film. The difference between n1 and n2 disappears with the vanishing of the Film spontaneous polarization in a paraelectric phase. The temperature transition from the Ferroelectric to paraelectric phase taking place in a strained Ferroelectric Film can be varied in a wide temperature range by an appropriate choice of misfit strain so that the first plateaus of the predicted IQHE effect can be observed even at room temperatures.We revealed that 180° domain walls in a strained Ferroelectric Film can induce p-n junctions in a graphene channel and lead to the nontrivial temperature and gate voltage dependences of the perpendicular modes of the integer quantum Hall effect (IQHE). In particular, the number of perpendicular modes v⊥, corresponding to the p-n junction across the graphene channel, varies with the gate voltage increase from small integers to higher non-integer numbers, e.g., v⊥ = 1.9, 2, …, 5.1, 6.875, …, 9.1, …, 23,…, 37.4, in the vicinity of the transition temperature from the Ferroelectric to paraelectric phase. The non-integer numbers and their irregular sequence principally differ from the sequence of non-integer numbers ν = 3/2, 5/3, … reported earlier. The unusual v⊥-numbers originate from significantly different numbers of the edge modes, ν1 and ν2, corresponding to different concentrations of carriers in the left (n1) and right (n2) domains of the p-n junction boundary. The concentrations n1 and n2 are determine...
-
ballistic conductivity of graphene channel with p n junction at Ferroelectric domain wall
Applied Physics Letters, 2016Co-Authors: Anna N Morozovska, Eugene A Eliseev, Maksym V StrikhaAbstract:The influence of a Ferroelectric domain wall on the ballistic conductance of a single-layer graphene channel in the graphene/physical gap/Ferroelectric Film heterostructure has been studied in the Wentzel-Kramers-Brillouin approximation. The self-consistent numerical simulation of the electric field and the space charge dynamics in the heterostructure, as well as the approximate analytical theory, show that the contact between the domain wall and the surface creates a p-n junction in the graphene channel. We calculated that the carrier concentration induced in graphene by uncompensated Ferroelectric dipoles originated from the abrupt spontaneous polarization change near the surface can reach values of about 1019 m−2, which are two orders of magnitude higher than those obtained for the graphene on non-Ferroelectric substrates. Therefore, we predict that the graphene channel with the p-n junction caused by the Ferroelectric domain wall would be characterized by rather a high ballistic conductivity. Moreover...