Current-voltage characteristics of ultrafine-grained ferroelectric Pb(Zr, Ti)O3 thin films

1994 ◽  
Vol 9 (6) ◽  
pp. 1484-1498 ◽  
Author(s):  
H. Hu ◽  
S.B. Krupanidhi
Keyword(s):  
Thin Films ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
High Resistivity ◽  
Ultrafine Grained ◽  
Current Voltage ◽  
Electrode Interface ◽  
Current Voltage Characteristics ◽  
Homogeneous Media ◽  
Limited Conduction

Room-temperature current-voltage dependence of ultrafine-grained ferroelectric Pb(Zr, Ti)O3 thin films has been investigated. Both strong varistor type behavior and space charge limited conduction (SCLC) were observed. Differences in the current-voltage characteristics are attributed to differences in the nature of the grain boundaries resulting from variations in processing conditions. The strong varistor type behavior is believed to be due to the presence of highly resistive grain boundaries and thus may be termed grain boundary limited conduction (GBLC). A double-depletion-layer barrier model is used to describe the origin of high resistivity of the grain boundaries. It is suggested that the barrier height varies significantly with the applied field due to the nonlinear ferroelectric polarization, and that the barrier is overcome by tunneling at sufficiently high fields. In some other cases, the resistivity of the grain boundaries is comparable to that of the grains, and therefore the intrinsically heterogeneous films degenerate into quasi-homogeneous media, to which the SCLC theory is applicable. As such, a unified grain boundary modeling reconciles different types of conduction mechanisms in the ultrafine-grained ferroelectric thin films. This grain boundary modeling also well accounts for some other dc-related phenomena observed, including abnormal current-voltage dependencies, remanent polarization effect, electrode interface effect, and unusual charging and discharging transients. In addition, many other electrical properties of the ferroelectric films may be better understood by taking the effect of grain boundaries into account.

Grain Boundary Atomic Structures in SrTiO3 and BaTiO3

2007 ◽  
Vol 558-559 ◽  
pp. 851-856 ◽  
Author(s):  
Takahisa Yamamoto ◽  
Teruyasu Mizoguchi ◽  
S.Y. Choi ◽  
Yukio Sato ◽  
Naoya Shibata ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Annealing Temperature ◽  
Unit Length ◽  
Rate Dependency ◽  
Atomic Structures ◽  
Current Voltage ◽  
Single Grain ◽  
Current Voltage Characteristics ◽  
Theoretical Results

SrTiO3 bicrystals with various types of grain boundaries were prepared by joining two single crystals at high temperature. By using the bicrystals, we examined their current-voltage characteristics across single grain boundaries from a viewpoint of point defect segregation in the vicinity of the grain boundaries. Current-voltage property in SrTiO3 bicrystals was confirmed to show a cooling rate dependency from annealing temperature, indicating that cation vacancies accumulate due to grain boundary oxidation. The theoretical results obtained by ab-initio calculation clearly showed that the formation energy of Sr vacancies is the lowest comparing with Ti and O vacancies in oxidized atomosphere. The formation of a double Schottky barrier (DSB) in n-type SrTiO3 is considered to be closely related to the accumulation of the charged Sr vacancies. Meanwhile, by using three types of low angle boundaries, the excess charges related to one grain boundary dislocation par unit length was estimated. In this study, we summarized our results obtained in our group.

Effects of Grain Boundaries in Amorphous/Multicrystalline Silicon Heterojunction Photovoltaic Cells

2004 ◽  
Vol 836 ◽  
Author(s):  
M. Farrokh Baroughi ◽  
S. Sivoththaman
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Dark Current ◽  
Spectral Response ◽  
Simulation Software ◽  
Multicrystalline Silicon ◽  
Consistent Difference ◽  
Photovoltaic Properties ◽  
Current Voltage ◽  
Current Voltage Characteristics

ABSTRACTSpectral response and dark current-voltage characteristics of heterojunctions are used to investigate grain boundary degradation in photovoltaic properties of a-Si/mc-Si heterojunction solar cells. Measured spectral response inside the grain and on the grain boundary shows small but consistent QE degradation due to minority carrier recombination at the grain boundaries. No consistent difference is observed in dark current-voltage characteristics because of large diode area and periphery leakage current in the employed heterojunction diodes. Comparing measurement results and results from device modeling using the simulation software Medici, a recombination velocity of 4900 cm/sec is found at the grain boundaries of employed multicrystalline silicon wafer. The modeling and experimental results can also be used to define an effective grain area that serves as a measure of grain boundary recombination and the influence of grain size.

Grain Boundaries in Crystallized Silicon Thin Films

1981 ◽  
Vol 5 ◽  
Author(s):  
N. M. Johnson ◽  
D. K. Biegelsen ◽  
M. D. Moyer
Keyword(s):  
Thin Films ◽  
Grain Boundaries ◽  
Secondary Ion Mass Spectrometry ◽  
Bulk Diffusion ◽  
Silicon Thin Films ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Silicon Islands ◽  
Device Operation ◽  
Secondary Ion

ABSTRACTThe presence of residual grain boundaries in laser-crystallized thin films of silicon necessitates an understanding of their properties and effects on device operation. In CW laser crystallized silicon islands, lateral p-n junction diodes have been used to evaluate the following: (1) enhanced arsenic diffusion along grain boundaries, (2) current-voltage characteristics, and (3) effects of hydrogenation on diode operation. To study the process of hydrogen passivation, deuterium has been used as a readily identifiable isotope which duplicates hydrogen chemistry. From secondary-ion mass spectrometry, diffusion of deuterium in single-crystal and polycrystalline silicon at low temperatures (e.g., 350 C) clearly demonstrates that grain-boundary diffusion dominates bulk diffusion.

Grain boundaries in zinc oxide-based varistor ceramics

1989 ◽  
Vol 47 ◽  
pp. 598-599
Author(s):  
Gun Yong Sung ◽  
Stuart McKernan ◽  
C. Barry Carter
Keyword(s):  
Zinc Oxide ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Breakdown Voltage ◽  
Research Effort ◽  
High Energy ◽  
Zno Varistor ◽  
Current Voltage ◽  
Highly Nonlinear ◽  
Current Voltage Characteristics

Since the development of the zinc oxide-based varistor with highly nonlinear current-voltage characteristics and high energy absorption capabilities [1], the electro-physical behavior of non-ohmic ZnO varistors has been studied and related to the microstructure of the material, the conduction and degradation mechanisms, the dielectric properties, and the high pressure memory. An extensive research effort has been aimed at characterizing ZnO/ZnO grain boundary regions in order to explain the origin of the nonlinear current/voltage characteristics of these materials [2-4]. A typical ZnO-varistor material contains small concentrations of several metal oxides (e.g., Bi2O3, CoO, MnO, Sb2O3, and Cr2O3). Co and Mn are contained within the ZnO grains, while the other “impurities are present as several polymorphic forms of Bi2O3, the spinel, Zn7Sb2O12, and the pyrochlore Zn2Bi3Sb3O14, are present as intergranular phases [1,5-7]. The breakdown voltage depends on the number of grain boundaries between the electrodes of the ZnO varistor device [8]. Therefore, the breakdown voltage is influenced by the presence and form of these intergranular phases, and the size, shape and distribution of the ZnO grains. In ZnO-Bi2O3-MnO-TiO2-based varistor materials, the morphology of the ZnO grains is strongly influenced by their tendency to grow preferentially along the directions perpendicular to the prism planes [9] (i.e., the basal plane becomes a common grain boundary facet plane). The aim of the present study is to advance the understanding of the role of the special grain boundaries which are found in air-quenched Zn0-Bi2O3-MnO-TiO2-based varistor materials.

scholarly journals Improved Device Distribution in High-Performance SiNx Resistive Random Access Memory via Arsenic Ion Implantation

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1401
Author(s):  
Te Jui Yen ◽  
Albert Chin ◽  
Vladimir Gritsenko
Keyword(s):  
High Performance ◽  
Conduction Mechanism ◽  
Random Access ◽  
Random Access Memory ◽  
Resistive Random Access Memory ◽  
Switching Behavior ◽  
Access Memory ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Limited Conduction

Large device variation is a fundamental challenge for resistive random access memory (RRAM) array circuit. Improved device-to-device distributions of set and reset voltages in a SiNx RRAM device is realized via arsenic ion (As+) implantation. Besides, the As+-implanted SiNx RRAM device exhibits much tighter cycle-to-cycle distribution than the nonimplanted device. The As+-implanted SiNx device further exhibits excellent performance, which shows high stability and a large 1.73 × 103 resistance window at 85 °C retention for 104 s, and a large 103 resistance window after 105 cycles of the pulsed endurance test. The current–voltage characteristics of high- and low-resistance states were both analyzed as space-charge-limited conduction mechanism. From the simulated defect distribution in the SiNx layer, a microscopic model was established, and the formation and rupture of defect-conductive paths were proposed for the resistance switching behavior. Therefore, the reason for such high device performance can be attributed to the sufficient defects created by As+ implantation that leads to low forming and operation power.

Preparation and Electrical Characteristics of (100), (111), and Randomly Oriented PZT Thin Films

1994 ◽  
Vol 361 ◽  
Author(s):  
Chang Jung Kim ◽  
Dae Sung Yoon ◽  
Joon Sung Lee ◽  
Chaun Gi Choi ◽  
Won Jong Lee ◽  
...  
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Hysteresis Loops ◽  
Test System ◽  
Electrical Characteristics ◽  
Pzt Thin Films ◽  
Pole Figures ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Drying Conditions

ABSTRACTThe (100), (111) and randomly oriented PZT thin films were fabricated on Pt/Ti/Coming 7059 glass using sol-gel method. The thin films having different orientation were fabricated by different drying conditions for pyrolysis. The preferred orientations of the PZT thin films were observed using XRD, rocking curves, and pole figures. The microstructures were investigated using SEM. The hysteresis loops and capacitance-voltage characteristics of the films were investigated using a standardized ferroelectric test system. The dielectric constant and current-voltage characteristics of the films were investigated using an impedance analyzer and pA meter, respectively. The films oriented in a particular direction showed superior electrical characteristics to the randomly oriented films.

Photoconductivity of Nanocomposite MEH-PPV: TiO2 Thin Films

2011 ◽  
Vol 13 ◽  
pp. 87-92 ◽  
Author(s):  
M.S.P Sarah ◽  
F.S. Zahid ◽  
M.Z. Musa ◽  
U.M. Noor ◽  
Z. Shaameri ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Surface Morphology ◽  
Spin Coating ◽  
Glass Substrate ◽  
Spin Coating Technique ◽  
Coating Technique ◽  
Current Voltage ◽  
Current Voltage Characteristics

The photoconductivity of a nanocomposite MEH-PPV:TiO2 thin film is investigated. The nanocomposite MEH-PPV:TiO2 thin film was deposited on a glass substrate by spin coating technique. The composition of the TiO2 powder was varied from 5 wt% to 20 wt% (with 5 wt% interval). The concentration of the MEH-PPV is given by 1 mg/1 ml. The current voltage characteristics were measured in dark and under illumination. The photoconductivity showed increment in value as the composition of the TiO2 is raised in the polymer based solution. The absorption showed augmentation as the amount of TiO2 is increased. The escalation of the current voltage is then supported by the results of surface morphology.

Sign in / Sign up

Export Citation Format

Share Document