Conductivity Mechanisms in Acceptor Doped KTaO3 Crystals

1990 ◽  
Vol 210 ◽  
Author(s):  
T. Scherban ◽  
S.Q. Fu ◽  
A.S. Nowick
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Oxygen Vacancy ◽  
Ionic Conduction ◽  
Electron Hole ◽  
Cu Doping ◽  
Hole Conduction ◽  
Protonic Conductors ◽  
Dry Conditions ◽  
Co Doped

AbstractThe electrical conductivity of perovskite—structured KTaO3 crystals acceptor doped with Co, Cu or Fe was investigated after treatments in oxidizing and reducing atmospheres under both wet and dry conditions. Isotope effect measurements (using H2O vs. D2O) show that, after treatments in wet gases of low P(O2), all the crystals are primarily protonic conductors, through a process of proton hopping with an activation energy close to 0.84 eV. Electron hole conduction dominatesat high P(O2) in the case of Fe and Cu doping. For Co—doped crystals, the conductivity is independent of P(O2) up to 1 atm., indicating that ionic conduction predominates. There is no evidence of oxygen vacancy migration, leading to the conclusion that the activation energy for that process Is relatively high.

Effect of Cu doping on the electrical Properties of ZnTe by Vacuum Thermal Evaporation

2018 ◽  
Vol 31 (3) ◽  
pp. 20
Author(s):  
Sarmad M. M. Ali ◽  
Alia A.A. Shehab ◽  
Samir A. Maki
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Hall Effect ◽  
Carrier Concentration ◽  
Hall Mobility ◽  
Cu Doping ◽  
Before And After ◽  
Hall Effect Measurements ◽  
Evaporation Technique ◽  
P Type

In this study, the ZnTe thin films were deposited on a glass substrate at a thickness of 400nm using vacuum evaporation technique (2×10-5mbar) at RT. Electrical conductivity and Hall effect measurements have been investigated as a function of variation of the doping ratios (3,5,7%) of the Cu element on the thin ZnTe films. The temperature range of (25-200°C) is to record the electrical conductivity values. The results of the films have two types of transport mechanisms of free carriers with two values of activation energy (Ea1, Ea2), expect 3% Cu. The activation energy (Ea1) increased from 29meV to 157meV before and after doping (Cu at 5%) respectively. The results of Hall effect measurements of ZnTe , ZnTe:Cu films show that all films were (p-type), the carrier concentration (1.1×1020 m-3) , Hall mobility (0.464m2/V.s) for pure ZnTe film, increases the carrier concentration (6.3×1021m-3) Hall mobility (2m2/V.s) for doping (Cu at 3%) film, but  decreases by increasing Cu concentration.

scholarly journals Influence of Mn, Fe, Co, and Cu Doping on the Photoelectric Properties of 1T HfS2 Crystals

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 173
Author(s):  
Der-Yuh Lin ◽  
Yu-Tai Shih ◽  
Wei-Chan Tseng ◽  
Chia-Feng Lin ◽  
Hone-Zern Chen
Keyword(s):  
Electron Microscopy ◽  
Activation Energy ◽  
Transition Metal Dichalcogenides ◽  
Chemical Vapor ◽  
Vital Role ◽  
Chemical Vapor Transport ◽  
Time Resolved ◽  
Cu Doping ◽  
Photoelectric Properties ◽  
Co Doped

Doping plays a vital role in the application of transition-metal dichalcogenides (TMDCs) because it can increase the functionality of TMDCs by tuning their native characteristics. In this study, the influence of Mn, Fe, Co, and Cu doping on the photoelectric properties of HfS2 was investigated. Pristine, Mn-, Fe-, Co-, and Cu-doped HfS2 crystals were grown using the chemical vapor transport method. Scanning electron microscopy images showed that the crystals were layered and transmission electron microscopy, X-ray diffraction, and Raman spectroscopy measurements confirmed that the crystals were in the 1T-phase with a CdI2-like structure. The bandgap of pristine HfS2 obtained from the absorption and photoconductivity spectra was approximately 1.99 eV. As the dopant changed from Mn, Fe, and Co, to Cu, the bandgap gradually increased. The activation energies of the samples were determined using temperature-dependent current-voltage curves. After doping, the activation energy decreased, and the Co-doped HfS2 exhibited the smallest activation energy. Time-resolved photoresponse measurements showed that doping improved the response of HfS2 to light; the Co-doped HfS2 exhibited the best response. The photoresponsivity of HfS2 as a function of the laser power and bias voltage was measured. After doping, the photoresponsivity increased markedly; the Co-doped HfS2 exhibited the highest photoresponsivity. All the experimental results indicated that doping with Mn, Fe, Co, and Cu significantly improved the photoresponsive performance of HfS2, of which Co-doped HfS2 had the best performance.

Ionic Conduction Mechanisms in CaF2 and CaF2-Al2O3 Nanocomposite Films on Al2O3 Substrates

1993 ◽  
Vol 318 ◽  
Author(s):  
F. A. Modine ◽  
D. Lubben ◽  
J. B. Bates
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Ionic Conduction ◽  
Electrical Conductance ◽  
High Conductivity ◽  
Nanocomposite Films ◽  
Second Phase ◽  
Mole Percent ◽  
Interdigital Electrodes

ABSTRACTThin films of pure CaF2 and nanocomposite mixtures of Al2O3 with CaF2 were sublimated on Al2O3 substrates. Interdigital electrodes allowed in situ measurements of the electrical conduction of films as a function of thickness, deposition rate, composition, time, and temperature. The electrical conductivity in pure CaF2 adjacent to an Al2O3 interface sometimes exceeded the bulk CaF2 conductivity (i.e., value at more than 50 nm distance) by as much as a factor of 6700 at 200°C. The high conductivity is characterized by an activation energy of 0.6 ± 0.1 eV, which is significantly lower than the activation energy of about 1.0 eV for conduction in the bulk. However, this high conductivity is thermally unstable and diminishes in time. A high but stable conductivity was obtained in CaF2 films containing about 10 mole percent Al2O3 as a dispersed second phase. At 200°C, a 2-phase film gave a factor of 360 enhancement over the measured bulk CaF2 conductivity and a factor of 7 improvement over the best previously reported conductivity for CaF2-Al203 composite materials. The origin of enhanced conduction in CaF2 is attributed to ion transport along dislocations. Dislocations anneal with a characteristic log of time dependence that is recognizable in the annealing behavior of the electrical conductivity. Presumably, the addition of a dispersed second phase of Al2O3 to CaF2 serves both to generate and to pin dislocations; the electrical conductance is thereby enhanced and stabilized.

Preparation of YSZ Electrolyte for SOFC by Electron Beam PVD

2006 ◽  
Vol 317-318 ◽  
pp. 913-916 ◽  
Author(s):  
Tae Ho Shin ◽  
Ji Heang Yu ◽  
Shi Woo Lee ◽  
In Sub Han ◽  
Sang Kuk Woo ◽  
...  
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Electron Beam ◽  
Vapor Deposition ◽  
Physical Vapor Deposition ◽  
Ionic Conduction ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
High Activation ◽  
Ysz Electrolyte

Yttria stabilized zirconia (YSZ) films with the thickness of up to 12 μm were prepared on alumina and NiO-YSZ substrates by electron beam physical vapor deposition (EB-PVD). The films showed nano-scaled columnar structures depending on the substrate temperature. Electrical conductivity of the YSZ films on alumina was also investigated at the temperature between 700 and 1000oC in oxidizing atmosphere. High activation energy of the conductivity (>1.03eV) indicated that the conduction via grain boundary controlled the ionic conduction in the films prepared by EB-PVD. La0.6Sr0.4CoO3-δ as a cathode was applied on the YSZ/NiO-YSZ in order to evaluate the performance of the YSZ electrolyte.

THE PREPARATION AND PROPERTIES OF POLYCRYSTALS OF SOLID ELECTROLYTE ULTRAFINE PARTICLES

1996 ◽  
Vol 03 (01) ◽  
pp. 41-44 ◽  
Author(s):  
T. IDA ◽  
H. SAEKI ◽  
H. HAMADA ◽  
K. KIMURA
Keyword(s):  
Activation Energy ◽  
Charge Transport ◽  
Solid Electrolyte ◽  
Transport Properties ◽  
Ultrafine Particles ◽  
Solid Electrolytes ◽  
Ionic Conduction ◽  
Submicron Particles ◽  
Hole Conduction ◽  
Enhanced Conductivity

We have investigated the transport properties of polycrystals of solid electrolytes, CuBr(I) , CuCl(I) , and AgI, by compressing submicron particles prepared by the evaporation method. The pellets of asgrown CuBr and CuCl particles tend to be contaminated by Cu(II), which may cause charge transport by hole conduction. After the CuCl particles are treated with acetone, the pellet shows significant ionic conduction. The pellet of purified particles 0.4-μ m CuCl has a conductivity of 5×10−7Ω−1 cm −1 at 25° C , and activation energy for conduction of 0.44 eV. The 0.7-μ m AgI pellet also shows an enhanced conductivity of 5×10−5Ω−1 cm −1 at 25°C, and activation energies of 0.04 eV between 60 and 5° C , and 0.23 eV below −25°C.

Optimizing physical properties of Co-doped ZnO nanoparticles: Controlling oxygen vacancy and carrier concentration

Vacuum ◽  
2021 ◽  
pp. 110488
Author(s):  
Huying Yan ◽  
Jian Xue ◽  
Wenjing Chen ◽  
Jialing Tang ◽  
Ling zhong ◽  
...  
Keyword(s):  
Oxygen Vacancy ◽  
Physical Properties ◽  
Carrier Concentration ◽  
Zno Nanoparticles ◽  
Doped Zno ◽  
Co Doped

scholarly journals Oxygen vacancy doping of hematite analyzed by electrical conductivity and thermoelectric power measurements

2017 ◽  
Vol 1 (6) ◽  
Author(s):  
Jan Mock ◽  
Benjamin Klingebiel ◽  
Florian Köhler ◽  
Maurice Nuys ◽  
Jan Flohre ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Oxygen Vacancy ◽  
Thermoelectric Power ◽  
Power Measurements ◽  
Vacancy Doping

Electrical Conductivity and Structural Studies on the Binary System BiI3-Ag2SO4

2012 ◽  
Vol 584 ◽  
pp. 521-525
Author(s):  
S. Austin Suthanthiraraj ◽  
Ayesha Saleem
Keyword(s):  
Electrical Conductivity ◽  
Binary System ◽  
Ionic Conduction ◽  
Structural Characteristics ◽  
Complex Impedance ◽  
Present System ◽  
Rapid Melt Quenching ◽  
Ionic Nature ◽  
Electrochemical Devices ◽  
Silver Sulphate

A new solid-state pseudo binary system BiI3_-Ag2SO4 involving bismuth triiodide (BiI3) and a silver oxysalt namely silver sulphate (Ag2SO4) has been prepared using rapid melt-quenching technique. AC conductivity studies have been carried out on the nine different samples of the (BiI3)x –- (Ag2SO4)(1-x) system with compositions corresponding to x=0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8 and 0.9 mole fraction at temperatures ranging from room temperature (298 K) to 433K. The bulk resistance values estimated using complex impedance plots indicated that electrical conductivity of the synthesized solid specimens would vary from 2.9 x10-2 to 3.4 x10-6Scm-1 thus suggesting the present system to be ionic in nature. The extent of ionic conduction due to Ag + cation has also been analyzed using Wagner’s dc polarization technique whereas detailed structural characteristics of the various compositions derived from Fourier transform infrared (FTIR) spectroscopy and features of surface morphology of these samples obtained using scanning electron microscopy (SEM) have further supported the ionic nature of the chosen system and suggested possible application as a solid electrolyte in electrochemical devices.

Tuning the electronic and structural properties of WO3 nanocrystals by varying transition metal tungstate precursors

RSC Advances ◽  
2014 ◽  
Vol 4 (107) ◽  
pp. 62423-62429 ◽  
Author(s):  
Sara Rahimnejad ◽  
Jing Hui He ◽  
Wei Chen ◽  
Kai Wu ◽  
Guo Qin Xu
Keyword(s):  
Methylene Blue ◽  
Transition Metal ◽  
Oxygen Vacancy ◽  
Band Gap ◽  
Azo Dye ◽  
Electron Hole ◽  
Recombination Time ◽  
Metal Tungstate ◽  
Electronic And Structural Properties ◽  
Hole Recombination

WO3 nanoplates derived from NiWO4 were found to have the highest concentration of oxygen vacancy, narrowest band gap, longest electron–hole recombination time, and in turn the highest rate of photodegradation of azo dye methylene blue.

Electrical conductivity of Co doped cuprous oxide

Ionics ◽  
1995 ◽  
Vol 1 (5-6) ◽  
pp. 488-490 ◽  
Author(s):  
Y. Tsur ◽  
I. Riess
Keyword(s):  
Electrical Conductivity ◽  
Cuprous Oxide ◽  
Co Doped
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