Effect of MnO on the Electrical Properties of Nb-Doped SrTiO3 Varistor

1998 ◽  
Vol 547 ◽  
Author(s):  
S.-H. Kim ◽  
H.-W. Seon ◽  
Yoonho Kim

AbstractThe effect of MnO on the electrical properties of Nb-doped SrTiO3 was investigated to understand the electronic states of grains and grain boundaries. Grain size and dielectric constant were decreased with increasing Mn-doped content from 0 to 0.07 mol%. However, it was observed that the non-linearity coefficient of Nb-doped SrTiO3 was changed from 5 to 43 with Mn-doped content increasing from 0 to 0.03 mol%. Current-voltage (I-V) characteristics, capacitance-voltage (C-V) measurement, complex plane analysis and impedance spectroscopy were performed to obtain the information about the electrical properties of grains and grain boundaries. The potential barrier height increased and the donor concentration decreased with increasing Mn-doped content. This phenomena, that the electrical properties of Nb-doped SrTiO3 were changed with the addition of Mn, would be determined by the effect which Mn-2-3 substituted for Ti sites. It was observed that the breakdown voltage of single grain boundary was changed from 3.8 V to 8.9 V when measured by micro-electrode method.

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3294
Author(s):  
Jakkree Boonlakhorn ◽  
Jedsada Manyam ◽  
Pornjuk Srepusharawoot ◽  
Sriprajak Krongsuk ◽  
Prasit Thongbai

The effects of charge compensation on dielectric and electrical properties of CaCu3Ti4-x(Al1/2Ta1/4Nb1/4)xO12 ceramics (x = 0−0.05) prepared by a solid-state reaction method were studied based on the configuration of defect dipoles. A single phase of CaCu3Ti4O12 was observed in all ceramics with a slight change in lattice parameters. The mean grain size of CaCu3Ti4-x(Al1/2Ta1/4Nb1/4)xO12 ceramics was slightly smaller than that of the undoped ceramic. The dielectric loss tangent can be reduced by a factor of 13 (tanδ ~0.017), while the dielectric permittivity was higher than 104 over a wide frequency range. Impedance spectroscopy showed that the significant decrease in tanδ was attributed to the highly increased resistance of the grain boundary by two orders of magnitude. The DFT calculation showed that the preferential sites of Al and Nb/Ta were closed together in the Ti sites, forming self-charge compensation, and resulting in the enhanced potential barrier height at the grain boundary. Therefore, the improved dielectric properties of CaCu3Ti4-x(Al1/2Ta1/4Nb1/4)xO12 ceramics associated with the enhanced electrical properties of grain boundaries. In addition, the non-Ohmic properties were also improved. Characterization of the grain boundaries under a DC bias showed the reduction of potential barrier height at the grain boundary. The overall results indicated that the origin of the colossal dielectric properties was caused by the internal barrier layer capacitor structure, in which the Schottky barriers at the grain boundaries were formed.


2007 ◽  
Vol 558-559 ◽  
pp. 851-856 ◽  
Author(s):  
Takahisa Yamamoto ◽  
Teruyasu Mizoguchi ◽  
S.Y. Choi ◽  
Yukio Sato ◽  
Naoya Shibata ◽  
...  

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.


1993 ◽  
Vol 320 ◽  
Author(s):  
A. Lauwers ◽  
A. Vercaemst ◽  
M. Van Hove ◽  
K. Kyllesbech Larsen ◽  
R. Verbeeck ◽  
...  

ABSTRACTIn this paper the electrical properties of epitaxial CoSi2 on Si obtained by solid-state reaction of a Ti/Co bimetallic layer are investigated. Low temperature resistivity, magnetoresistance and Hall data are presented. The CoSi2ISi Schottky diodes are characterised by current - voltage and capacitance - voltage measurements at temperatures varying between - 100°C and 60°C.


1995 ◽  
Vol 411 ◽  
Author(s):  
T. D. Chen ◽  
J.-R. Lee ◽  
H. L. Tuller ◽  
Y.-M. Chiang

ABSTRACTSimplified varistor systems of bismuth- and cobalt-doped zinc oxide are studied. A prior study has shown that the distributions of bismuth segregation at the grain boundaries in such samples can be controlled by varying microstructure and heat treatment. Current-voltage and deep level transient spectroscopy measurements were done to evaluate the corresponding electrical properties. Low leakage and α values of ˜30 were attained, despite the nominal, twocomponent doping of these simplified varistors. Moreover, these samples show the signature defects that are found in many multi-dopant, commercial devices: two shallow bulk traps at ˜0.14 eV and ˜0.24 eV and one prominent interfacial trap at ˜1 eV.


2013 ◽  
Vol 717 ◽  
pp. 117-120
Author(s):  
Budsara Nararug ◽  
Itsara Srithanachai ◽  
Surada Ueamanapong ◽  
Sanya Khunkhao ◽  
Supakorn Janprapha ◽  
...  

This paper analyzes the effect of X-ray irradiation on the electrical properties of Pt-doped p-n diode. X-ray energy irradiated on Pt-doped P-N diode with 70 keV with time 205 sec. After irradiations, the current-voltage (I-V) characteristics and capacitance-voltage (C-V) characteristics and carrier degeneration lifetime (τg) were investigated. The results show that the leakage current is slightly increased after the diodes were exposed X-ray and affect higher degeneration carrier lifetime. The effects after X-ray irradiation indicated that the defects of the diode have been changed.


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Reşit Özmenteş ◽  
Cabir Temirci

AbstractIn this study, CuO/n-Si/Al heterojunction contacts were fabricated by thermal evaporation technique. Electrical characteristics of the samples were investigated with the current-voltage (I-V), capacitance-voltage/frequency (C-V/f), and conductance-voltage (G/V) measurements at room temperature. Also, Cu/n-Si/Al Schottky contact was produced as a reference sample to investigate the electrical properties of the samples. The values of ideality factor (n), barrier height (Φb) and series resistance (Rs) of the samples were calculated from the forward bias current-voltage (I-V) and reverse bias capacitance-voltage (C-V) characteristics. Also, for checking the consistency of the results, Cheung and Norde functions were used. The experimental result values of CuO/n-Si contact were compared with the values of the reference Cu/n-Si Schottky diode. It was observed that the values of the ideality factor and barrier height of the CuO/n-Si heterojunction were higher than those of the Cu/n-Si Schottky contact, while the series resistance was lower. Also, it has been observed that the value of capacitance decreased with increasing frequency and after a certain value of frequency it was almost constant. The ideality factor of CuO/n-Si/Al heterostructure is about 2.40 and so, it is not close to the ideal behavior.


1992 ◽  
Vol 242 ◽  
Author(s):  
J.W. Glesener ◽  
A.A. Morrish ◽  
K.A. Snail

ABSTRACTSchottky diodes were fabricated from boron doped diamond grown in a turbulent flame. The substrates used were type IIa diamond (100) crystals 1.5 mm in diameter and.25 mm thick. A p/p+ structure was deposited using the p+ layer as an ohmic contact. Current-voltage (I-V) and capacitance-voltage (C-V) measurements were made on the finished devices. An ideality factor of 1.8 was obtained from the I-V characteristics. Doping levels from C-V measurements indicate an acceptor concentration on the order of 5 × 1017/cm3.


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