A linear diffusion model for ion current across blocking grain boundaries in oxygen-ion and proton conductors

2014 ◽  
Vol 16 (28) ◽  
pp. 14961-14968 ◽  
Author(s):  
Seong K. Kim ◽  
Sergey Khodorov ◽  
Igor Lubomirsky ◽  
Sangtae Kim
Keyword(s):  
Grain Boundaries ◽  
Diffusion Model ◽  
Solid Electrolytes ◽  
Proton Conductors ◽  
Ion Current ◽  
Linear Diffusion ◽  
Oxygen Ion ◽  
Current Voltage ◽  
Current Voltage Characteristics

We demonstrate the applicability of the linear diffusion model recently proposed for the current–voltage characteristics of grain boundaries in solid electrolytes.

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.

Applicability of a linear diffusion model to determination of the height of the potential barrier at the grain boundaries of Fe-doped SrTiO3

2018 ◽  
Vol 20 (28) ◽  
pp. 19250-19256 ◽  
Author(s):  
Chih-Yuan S. Chang ◽  
Igor Lubomirsky ◽  
Sangtae Kim
Keyword(s):  
Grain Boundaries ◽  
Diffusion Model ◽  
Potential Barrier ◽  
Experimental Verification ◽  
Electron Hole ◽  
Linear Diffusion

Experimental verification of a linear diffusion model on a lightly doped electron–hole conductor, Fe-doped SrTiO3.

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.

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