scholarly journals Defect Structure of the Mixed-Conducting Sr-Fe-Co-O System

1996 ◽  
Vol 453 ◽  
Author(s):  
B. Ma ◽  
U. Balachandran ◽  
C.-C. Chao ◽  
J.-H. Park
Keyword(s):  
Activation Energy ◽  
Defect Structure ◽  
Elevated Temperatures ◽  
Ionic Conductivities ◽  
Transition Metal Ions ◽  
Partial Pressures ◽  
Conduction Behavior ◽  
Increasing Temperature ◽  
P Type ◽  
Type Conduction

AbstractElectrical conductivity of the mixed-conducting Sr-Fe-Co-O system was investigated at elevated temperatures and various oxygen partial pressures (pO2). The system exhibits not only high combined electrical and oxygen ionic conductivities but also structural stability in both oxidizing and reducing environments. The conductivity of SrFeCo0.5Ox increases with increasing temperature and increasing pO2, within our experimental pO2 range (1 ≥ pO2 ≥ 1O-18 atm). p-type conduction behavior was observed. The activation energy of which increases with decreasing pO2. A model of the defect chemistry in the Sr-Fe-Co-O system is proposed. The pO2-dependent conducting behavior can be understood by considering the trivalent-to-divalent transition of the transition metal ions in the system.

Oxygen Sensitivity of SrFeO3-δ Thin Films Prepared by Sol-Gel Method

2007 ◽  
Vol 280-283 ◽  
pp. 315-318 ◽  
Author(s):  
Chong Liang ◽  
De An Yang ◽  
Jian Jing Song ◽  
Ming Xia Xu
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Grain Size ◽  
Sol Gel ◽  
Alumina Substrate ◽  
Oxygen Sensitivity ◽  
Coating Film ◽  
Partial Pressures ◽  
P Type ◽  
Type Conduction

Sr(NO3)2, Fe(NO3)3 and citric acid (the mole ratio was 1:1:2) were mixed in water to form sol. Alumina substrate, which had been treated by ultrasonic cleaner, were dipped in the sol and pulled out, and the coating film was heated for 1h at 900oC. Through seventeen times treatment, SrFeO3-d thin film was coated on the alumina substrate. The remainder sol was dried and heated at 400oC, 800oC, 900oC for 2 h. The thin films and the powders were characterized by XRD. The morphologies of thin films were observed by SEM. The results showed that SrFeO3-δ was formed at 900oC on alumina substrate and the grain size was 100 ~ 200 nm. The oxygen sensitivity was measured in the temperature range of 377 ~ 577oC under different oxygen partial pressures. SrFeO3-δ thin film showed p-type conduction. The response time was less than 2 min when being exposed to a change from N2 to 0.466% O2 at 377oC.

Effects of magnesium on phosphorus chemical states and p-type conduction behavior of phosphorus-doped ZnO films

2013 ◽  
Vol 138 (3) ◽  
pp. 034704 ◽  
Author(s):  
Jichao Li ◽  
Yongfeng Li ◽  
Bin Yao ◽  
Ying Xu ◽  
Shiwang Long ◽  
...  
Keyword(s):  
Zno Films ◽  
Conduction Behavior ◽  
Chemical States ◽  
Doped Zno ◽  
P Type ◽  
Phosphorus Doped ◽  
Type Conduction

Influence of Ag–S codoping on silver chemical states and stable p-type conduction behavior of the ZnO films

2014 ◽  
Vol 40 (1) ◽  
pp. 2161-2167 ◽  
Author(s):  
Y. Xu ◽  
T. Yang ◽  
B. Yao ◽  
Y.F. Li ◽  
Z.H. Ding ◽  
...  
Keyword(s):  
Zno Films ◽  
Conduction Behavior ◽  
Chemical States ◽  
P Type ◽  
Type Conduction

scholarly journals Role of Structure and Composition on the Performances of p-Type Tin Oxide Thin-Film Transistors Processed at Low-Temperatures

2019 ◽  
Author(s):  
Raquel Barros ◽  
Kachirayil J. Saji ◽  
João C. Waerenborgh ◽  
Pedro Barquinha ◽  
Luis Pereira ◽  
...  
Keyword(s):  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Rf Magnetron Sputtering ◽  
Spectroscopic Studies ◽  
Oxide Thin Film ◽  
Partial Pressures ◽  
P Type ◽  
Type Conduction

This work reports the role of structure and composition on the determination of the performances of p-type SnOx TFTs deposited by rf magnetron sputtering at room temperature, followed by a post-annealed step up to 200 °C at different oxygen partial pressures (Opp), between 0% and 20%, but where the p-type conduction was only observed between 2.8–3.8%. The role of structure and composition were evaluated by XRD and Mössbauer spectroscopic studies. The study allows to identify the best phases/compositions and thicknesses (around 12 nm) to be used that lead to the production of TFTs with a bottom gate configuration, on glasses coated with conductive Indium Tin Oxide, followed by Aluminium Titanium Oxide dielectric layer with saturation mobility of 4.6 cm2V−1s−1 and on-off ratio above 7 × 104, operating at the enhancement mode with a saturation voltage of −10 V.

scholarly journals Phase Stability of The Mixed-Conducting Sr-Fe-Co-O System

1997 ◽  
Vol 496 ◽  
Author(s):  
B. Ma ◽  
U. Balachandran ◽  
J. P. Hodges ◽  
J. D. Jorgensen ◽  
D. J. Miller ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Elevated Temperatures ◽  
Cobalt Content ◽  
Ceramic Membranes ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Ceramic Oxides ◽  
Partial Pressures ◽  
Dense Ceramic ◽  
Increasing Temperature

ABSTRACTMixed-conducting ceramic oxides have potential uses in high-temperature electrochemical applications such as solid oxide fuel cells, batteries, sensors, and oxygen-permeable membranes. The Sr-Fe-Co-O system combines high electronic/ionic conductivity with appreciable oxygen permeability at elevated temperatures. Dense ceramic membranes made of this material can be used to separate high-purity oxygen from air without the need for external electrical circuitry, or to partially oxidize methane to produce syngas. Samples of Sr2Fe3-xCoxOy (with x = 0,0.6,1.0, and 1.4) were prepared by solid-state reaction method in atmospheres with various oxygen partial pressures (pO2) and were characterized by X-ray diffraction, scanning electron microscopy, and electrical conductivity testing. Phase components of the sample are dependent on cobalt concentration and pO2. Electrical conductivity increases with increasing temperature and cobalt content in the material.

scholarly journals Investigation of Electronic Conductivity in PbI2:Hf Single Crystals

2019 ◽  
Vol 20 (4) ◽  
pp. 396-400
Author(s):  
T.V. Furs ◽  
O.I. Hulaj ◽  
V.Ya. Shemet
Keyword(s):  
Activation Energy ◽  
Single Crystal ◽  
Single Crystals ◽  
Electronic Conductivity ◽  
Hole Conductivity ◽  
Electron Hole ◽  
Upper Limit ◽  
Increasing Temperature ◽  
P Type ◽  
Current Potential

A study of the electron-hole conductivity in PbI2 single crystals doped with Hf (0.2 wt %) was conducted using the Wagner polarization cell method. The influence of the Hf alloying admixture (0.2 mass%) on the nature and parameters of lead diiodide’s electronic conductivity has been analyzed. Basing on the received current-potential dependences, p-type conductivity of a single crystal PbI2:Hf was established. The hole conductivity values (sро) were determined in the studied temperature range allowing to construct temperature dependence. The sро value for single crystal PbI2:Hf increased responsively to increasing temperature. For PbI2 and PbI2:Hf, a comparative analysis of the electron-hole conductivity was carried out. This investigation allowed determining the activation energy sро reduction from 0.47 eV to 0.32 eV due to hafnium doping. Consequently, the presence of Hf admixture in PbI2 crystals causes new impurity acceptor levels located at a distance of 0.64 eV from the upper limit of the valence zone.

scholarly journals Indium-Nitrogen Codoped Zinc Oxide Thin Film Deposited by Ultrasonic Spray Pyrolysis on n-(111) Si Substrate: The Effect of Film Thickness

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Cheng-Chang Yu ◽  
Wen-How Lan ◽  
Kai-Feng Huang
Keyword(s):  
Activation Energy ◽  
Zinc Oxide ◽  
Film Thickness ◽  
Spray Pyrolysis ◽  
Hole Concentration ◽  
Hall Effect Measurement ◽  
Oxide Thin Film ◽  
Si Substrate ◽  
P Type ◽  
Type Conduction

Indium-nitrogen codoped zinc oxide (INZO) thin films were fabricated by spray pyrolysis deposition technique on n-(111) Si substrate with different film thicknesses at 450°C using a precursor containing zinc acetate, ammonium acetate, and indium nitrate with 1 : 3 : 0.05 at.% concentration. The morphology and structure studies were carried out by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The grain size of the films increased when increasing the film thickness. From XRD spectra, polycrystalline ZnO structure can be observed and the preferred orientation behavior varied from (002) to (101) as the film thickness increased. The concentration and mobility were investigated by Hall effect measurement. the p-type films with a hole mobility around 3 cm2V−1s−1and hole concentration around3×1019 cm−3can be achieved with film thickness less than 385 nm. The n-type conduction with concentration1×1020 cm−3is observed for film with thickness 1089 nm. The defect states were characterized by photoluminescence. With temperature-dependent conductivity analysis, acceptor state with activation energy 0.139 eV dominate the p type conduction for thin INZO film. And the Zn-related shallow donors with activation energy 0.029 eV dominate the n-type conduction for the thick INZO film.

scholarly journals Role of Structure and Composition on the Performances of P-Type Tin Oxide Thin-Film Transistors Processed at Low-Temperatures

Nanomaterials ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 320 ◽  
Author(s):  
Raquel Barros ◽  
Kachirayil Saji ◽  
João Waerenborgh ◽  
Pedro Barquinha ◽  
Luís Pereira ◽  
...  
Keyword(s):  
Room Temperature ◽  
Rf Magnetron Sputtering ◽  
Spectroscopic Studies ◽  
Oxide Thin Film ◽  
Enhancement Mode ◽  
Partial Pressures ◽  
P Type ◽  
Type Conduction

This work reports on the role of structure and composition on the determination of the performances of p-type SnOx TFTs with a bottom gate configuration deposited by rf magnetron sputtering at room temperature, followed by a post-annealed step up to 200 °C at different oxygen partial pressures (Opp) between 0% and 20% but where the p-type conduction was only observed between in a narrow window, from 2.8% to 3.8%. The role of structure and composition were evaluated by XRD and Mössbauer spectroscopic studies that allows to identify the best phases/compositions and thicknesses (around 12 nm) to be used to produce p-type TFTs with saturation mobility of 4.6 cm2 V−1 s−1 and on-off ratio above 7 × 104, operating at the enhancement mode with a saturation voltage of −10 V. Moreover, a brief overview is also presented concerning the present state of the existing developments in processing SnOx TFTs with different methods and using different device configurations.

The n-p Transition in YBa2Cu3O6–5+x

1987 ◽  
Vol 99 ◽  
Author(s):  
G. M. Choi ◽  
H. L. Tuller ◽  
M.-J. Tsai
Keyword(s):  
Elevated Temperatures ◽  
Unusual Behavior ◽  
Annealing Conditions ◽  
Oxygen Excess ◽  
Computer Controlled ◽  
Citrate Precursors ◽  
Power Measurements ◽  
P Type ◽  
Type Conduction

ABSTRACTThe role of annealing conditions on the equilibrium defect state of the material was investigated by computer controlled 4 probe d.c. conductivity and thermoelectric power measurements on dense homogeneous ceramics prepared from citrate precursors. At elevated temperatures, the conductivity first decreases and then increases exponentially with decreasing temperature with the conductivity minima shifting to lower temperatures with decreasing PO2. This unusual behavior is described as representing a transition from n-type to p-type conduction. The n-p transition is correlated with the corresponding stoichiometry shift upon cooling from oxygen deficient (Cu1, Cu2) to oxygen excess YBa3Cu3O6–5+x, (Cu2+, Cu3+). A preliminary defect model is proposed which provides a framework for understanding a number of the experimental observations.

Effects of (P, N) dual acceptor doping on band gap and p-type conduction behavior of ZnO films

2013 ◽  
Vol 113 (13) ◽  
pp. 133101 ◽  
Author(s):  
Yingrui Sui ◽  
Bin Yao ◽  
Li Xiao ◽  
Guozhong Xing ◽  
Lili Yang ◽  
...  
Keyword(s):  
Band Gap ◽  
Zno Films ◽  
Acceptor Doping ◽  
Conduction Behavior ◽  
P Type ◽  
Type Conduction
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