Physical and electrical characterization of sol-gel derived BaxSr1-xTiO3 thin films of various composition ratios and thicknesses
Among the various dielectric materials, barium strontium titanate has been extensively studied due to its high dielectric constant, low dielectric loss and high tunability. Barium strontium titanate is a composition dependent to Curie temperature, which decreases linearly with the increasing of S...
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| Format: | Thesis |
| Language: | English |
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| Online Access: | http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/32422/1/Page%201-24.pdf http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/32422/2/Full%20text.pdf |
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| Summary: | Among the various dielectric materials, barium strontium titanate has been
extensively studied due to its high dielectric constant, low dielectric loss and high
tunability. Barium strontium titanate is a composition dependent to Curie temperature,
which decreases linearly with the increasing of Sr amount in the composition. In this study, barium strontium titanate thin films with four different compositions; Ba0.5Sr0.5TiO3, Ba0.6Sr0.4TiO3, Ba0.7Sr0.3TiO3 and Ba0.8Sr0.2TiO3 and four different thicknesses were
prepared by using sol-gel technique and deposited on Pt/SiO2/Si substrates. The wellcrystallized,dense, smooth and crack-free thin films are obtained through annealing
process at temperature of 800 C. The dielectric constant, tunability and dielectric loss
shows strong relationship with the films microstructure. The dielectric constant, tunability and dielectric loss increases as the grain size and film thickness increases. The variations of
dielectric constant as a function of voltage for Ba0.5Sr0.5TiO3 and Ba0.6Sr0.4TiO3 thin films
are devoid of any spontaneous polarization, which indicates that the thin film is paraelectric
in room temperature. However, Ba0.7Sr0.3TiO3 and Ba0.8Sr0.2TiO3 thin films with butterflyshaped
curves show the existence of ferroelectric nature. The highest dielectric constant
and tunability, 485.02 and 34.75 % were observed in Ba0.7Sr0.3TiO3 composition at
thickness of 447.6 nm due to the Curie temperature of Ba0.7Sr0.3TiO3 is close to room
temperature. This work demonstrates successful physical and electrical characterization of
multiple layers of BaxSr1-xTiO3 thin films to its different composition ratios of Ba and Sr. |
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