Grain Boundary Defects Induced Switching in Zn- Bi- Mo Ceramic |
| Journal |
Defect and Diffusion Forum (Volumes 251 - 252) |
| Volume |
Defects and Diffusion Ceramics Abstracts |
| Edited by |
David J. Fisher |
| Pages |
13-20 |
| DOI |
10.4028/www.scientific.net/DDF.251-252.13 |
| Online since |
March, 2006 |
| Authors |
M. El-Hofy
|
| Keywords |
Grain Boundary Defects, Microstructure, Non-Ohmic Characteristics, Voltage Switching, ZnO-Mo Ceramic Doped Bi |
| Abstract |
Three Zinc Molybdenum ceramic samples doped Bi have been prepared according to the
chemical formula (1-x) ZnO – 0.2MoO3 – xBi2O3, where (x = 0.2, 0.5, 1.0) mol %. The samples were
studied at room temperature through X-ray Diffraction analysis, SEM, EDAX, I-V characteristics and
C-V measurements. The results decleared the presences of two phases; ZnO as a major phase beside
Bi2MoO6 as a minor phase. At lower Bi additions; Bi and Mo ions are highly segregated at the grain
boundaries, while at higher additions more homogenous distribution for these ions inside the grain is
observed. Some pores are observed around the batches of the minor phase and at the grain
boundaries. The grain size is enlarged with increasing Bi addition; while the number and size of the
pores are decrease. Creation of the pores is attributed to oxygen liberation from the surface of the
sample during sintering. Formation of Schottky barrier is indicated via I-V and C-V measurements
and attributed to Zn vacancies at the grain boundary. Interface potential barrier, donor density,
interface state density and barrier width are decrease with increasing Bi addition. I-V characteristics
revealed voltage switching. The switching voltage E0 decreases with increasing Bi addition and it is
reproducible even after several on-off cycles. |
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