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A Meliorated Multi-Frequency Band Pyroelectric Sensor.

Hsiao CC, Liu SY, Siao AS - Sensors (Basel) (2015)

Bottom Line: The proposed sensor is built on a silicon substrate with a thermal isolation layer of a silicon nitride film, consisting of four pyroelectric layers with various thicknesses deposited by a sputtering or aerosol deposition (AD) method and top and bottom electrodes.The fabricated device is effective in the range of 1 KHz~10 KHz with a rapid response and high voltage responsivity, while the ZnO layers with thicknesses of about 0.8 μm, 6 μm, 10 μm and 16 μm are used for fabricating the meliorated multi-frequency band pyroelectric sensor.The proposed sensor is successfully designed, analyzed, and fabricated in the present study, and can indeed extend the sensing range of the multi-frequency band.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Design Engineering, National Formosa University, No. 64, Wunhua Rd., Huwei Township, Yunlin County 632, Taiwan. cchsiao@nfu.edu.tw.

ABSTRACT
This article proposes a meliorated multi-frequency band pyroelectric sensor for detecting subjects with various velocities, namely extending the sensing frequency under good performance from electrical signals. A tactic, gradually increasing thickness of the ZnO layers, is used for redeeming drawbacks of a thicker pyroelectric layer with a tardy response at a high-frequency band and a thinner pyroelectric layer with low voltage responsivity at a low-frequency band. The proposed sensor is built on a silicon substrate with a thermal isolation layer of a silicon nitride film, consisting of four pyroelectric layers with various thicknesses deposited by a sputtering or aerosol deposition (AD) method and top and bottom electrodes. The thinnest ZnO layer is deposited by sputtering, with a low thermal capacity and a rapid response shoulders a high-frequency sensing task, while the thicker ZnO layers are deposited by AD with a large thermal capacity and a tardy response shoulders a low-frequency sensing task. The fabricated device is effective in the range of 1 KHz~10 KHz with a rapid response and high voltage responsivity, while the ZnO layers with thicknesses of about 0.8 μm, 6 μm, 10 μm and 16 μm are used for fabricating the meliorated multi-frequency band pyroelectric sensor. The proposed sensor is successfully designed, analyzed, and fabricated in the present study, and can indeed extend the sensing range of the multi-frequency band.

No MeSH data available.


Two-dimensional numerical model for the multi-frequency band ZnO pyroelectric sensor.
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sensors-15-16248-f002: Two-dimensional numerical model for the multi-frequency band ZnO pyroelectric sensor.

Mentions: That is, the higher the temperature variation rate in pyroelectric films, the higher the response of the pyroelectric sensors. However, the temperature variation field is difficult to extract from thin films by experimental measurements. Hsiao et al. [2,3,8] also used commercial multiphysics software, COMSOL MULTIPHYSICS® (Stockholm, Sweden), to explore the temperature variation rates in ZnO pyroelectric devices in the designing and optimizing of a partially covered mesh-type electrode. In the present study, a two-dimensional finite element model was constructed using the commercial multiphysics software, COMSOL MULTIPHYSICS® 4.2, to explore the temperature variation rate in meliorated multi-frequency band ZnO pyroelectric sensors. The materials’ properties of the films and substrate are shown in Table 4. There was an isotropic assumption for the films and substrate properties in this model. The model was meshed using a regular mesh, as shown in Figure 2. The thickness of the sputtered ZnO layer (TPZ) was fixed as 0.3 μm, while the thicknesses of the aerosol ZnO layers (TAZ1, TAZ2, TAZ3) were 3, 1 and 0.6 μm. The incident irradiation power applied on the top side of the meliorated multi-frequency band pyroelectric device was nearly 1.228 × 10−12 W/μm2 [15]. The thermal isolation condition was applied to the rear side of the silicon substrate, and the symmetric condition was applied to the two lateral sides as boundary conditions.


A Meliorated Multi-Frequency Band Pyroelectric Sensor.

Hsiao CC, Liu SY, Siao AS - Sensors (Basel) (2015)

Two-dimensional numerical model for the multi-frequency band ZnO pyroelectric sensor.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4541877&req=5

sensors-15-16248-f002: Two-dimensional numerical model for the multi-frequency band ZnO pyroelectric sensor.
Mentions: That is, the higher the temperature variation rate in pyroelectric films, the higher the response of the pyroelectric sensors. However, the temperature variation field is difficult to extract from thin films by experimental measurements. Hsiao et al. [2,3,8] also used commercial multiphysics software, COMSOL MULTIPHYSICS® (Stockholm, Sweden), to explore the temperature variation rates in ZnO pyroelectric devices in the designing and optimizing of a partially covered mesh-type electrode. In the present study, a two-dimensional finite element model was constructed using the commercial multiphysics software, COMSOL MULTIPHYSICS® 4.2, to explore the temperature variation rate in meliorated multi-frequency band ZnO pyroelectric sensors. The materials’ properties of the films and substrate are shown in Table 4. There was an isotropic assumption for the films and substrate properties in this model. The model was meshed using a regular mesh, as shown in Figure 2. The thickness of the sputtered ZnO layer (TPZ) was fixed as 0.3 μm, while the thicknesses of the aerosol ZnO layers (TAZ1, TAZ2, TAZ3) were 3, 1 and 0.6 μm. The incident irradiation power applied on the top side of the meliorated multi-frequency band pyroelectric device was nearly 1.228 × 10−12 W/μm2 [15]. The thermal isolation condition was applied to the rear side of the silicon substrate, and the symmetric condition was applied to the two lateral sides as boundary conditions.

Bottom Line: The proposed sensor is built on a silicon substrate with a thermal isolation layer of a silicon nitride film, consisting of four pyroelectric layers with various thicknesses deposited by a sputtering or aerosol deposition (AD) method and top and bottom electrodes.The fabricated device is effective in the range of 1 KHz~10 KHz with a rapid response and high voltage responsivity, while the ZnO layers with thicknesses of about 0.8 μm, 6 μm, 10 μm and 16 μm are used for fabricating the meliorated multi-frequency band pyroelectric sensor.The proposed sensor is successfully designed, analyzed, and fabricated in the present study, and can indeed extend the sensing range of the multi-frequency band.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Design Engineering, National Formosa University, No. 64, Wunhua Rd., Huwei Township, Yunlin County 632, Taiwan. cchsiao@nfu.edu.tw.

ABSTRACT
This article proposes a meliorated multi-frequency band pyroelectric sensor for detecting subjects with various velocities, namely extending the sensing frequency under good performance from electrical signals. A tactic, gradually increasing thickness of the ZnO layers, is used for redeeming drawbacks of a thicker pyroelectric layer with a tardy response at a high-frequency band and a thinner pyroelectric layer with low voltage responsivity at a low-frequency band. The proposed sensor is built on a silicon substrate with a thermal isolation layer of a silicon nitride film, consisting of four pyroelectric layers with various thicknesses deposited by a sputtering or aerosol deposition (AD) method and top and bottom electrodes. The thinnest ZnO layer is deposited by sputtering, with a low thermal capacity and a rapid response shoulders a high-frequency sensing task, while the thicker ZnO layers are deposited by AD with a large thermal capacity and a tardy response shoulders a low-frequency sensing task. The fabricated device is effective in the range of 1 KHz~10 KHz with a rapid response and high voltage responsivity, while the ZnO layers with thicknesses of about 0.8 μm, 6 μm, 10 μm and 16 μm are used for fabricating the meliorated multi-frequency band pyroelectric sensor. The proposed sensor is successfully designed, analyzed, and fabricated in the present study, and can indeed extend the sensing range of the multi-frequency band.

No MeSH data available.