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Uncooled Infrared Detector Featuring Silicon based Nanoscale Thermocouple

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Date Issued:
2016
Abstract/Description:
The main focus of this dissertation is to improve the performance of thermoelectric (TE)infrared (IR) detectors. TE IR detectors are part of uncooled detectors that can operate at roomtemperature. These detectors have been around for many years, however, their performance hasbeen lower than their contesting technologies. A novel high-responsivity uncooled thermoelectricinfrared detector is designed, fabricated, and characterized. This detector features a single standalonepolysilicon-based thermocouple (without a supporting membrane) covered by an umbrellalikeoptical-cavity IR absorber. It is proved that the highest responsivity in the developed detectorscan be achieved with only one thermocouple. Since the sub-micrometer polysilicon TE wires arethe only heat path from the hot junction to the substrate, a superior thermal isolation is achieved.A responsivity of 1800 V/W and a detectivity of 2 ? 10^8 (cm. sqrt(Hz)W^?1) are measured from a20?m x 20?m detector comparable to the performance of detectors used in commercial focalplanar arrays. This performance in a compact and manufacturable design elevates the position ofthermoelectric IR sensors as a candidate for low-power, high performance, and inexpensive focalplanar arrays. The improvement in performance is mostly due to low thermal conductivity of thinpolysilicon wires. A feature is designed and fabricated to characterize the thermal conductivity ofsuch a wire and it is shown for the first time that the thermal conductivity of thin polysilicon filmscan be much lower than that of the bulk. Thermal conductivity of ~110nm LPCVD polysilicondeposited at 620C is measured to be ~3.5W/m.K.
Title: Uncooled Infrared Detector Featuring Silicon based Nanoscale Thermocouple.
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Name(s): Modarres-Zadeh, Mohammad, Author
Abdolvand, Reza, Committee Chair
Sundaram, Kalpathy, Committee CoChair
Yuan, Jiann-Shiun, Committee Member
Malocha, Donald, Committee Member
Cho, Hyoung Jin, Committee Member
University of Central Florida, Degree Grantor
Type of Resource: text
Date Issued: 2016
Publisher: University of Central Florida
Language(s): English
Abstract/Description: The main focus of this dissertation is to improve the performance of thermoelectric (TE)infrared (IR) detectors. TE IR detectors are part of uncooled detectors that can operate at roomtemperature. These detectors have been around for many years, however, their performance hasbeen lower than their contesting technologies. A novel high-responsivity uncooled thermoelectricinfrared detector is designed, fabricated, and characterized. This detector features a single standalonepolysilicon-based thermocouple (without a supporting membrane) covered by an umbrellalikeoptical-cavity IR absorber. It is proved that the highest responsivity in the developed detectorscan be achieved with only one thermocouple. Since the sub-micrometer polysilicon TE wires arethe only heat path from the hot junction to the substrate, a superior thermal isolation is achieved.A responsivity of 1800 V/W and a detectivity of 2 ? 10^8 (cm. sqrt(Hz)W^?1) are measured from a20?m x 20?m detector comparable to the performance of detectors used in commercial focalplanar arrays. This performance in a compact and manufacturable design elevates the position ofthermoelectric IR sensors as a candidate for low-power, high performance, and inexpensive focalplanar arrays. The improvement in performance is mostly due to low thermal conductivity of thinpolysilicon wires. A feature is designed and fabricated to characterize the thermal conductivity ofsuch a wire and it is shown for the first time that the thermal conductivity of thin polysilicon filmscan be much lower than that of the bulk. Thermal conductivity of ~110nm LPCVD polysilicondeposited at 620C is measured to be ~3.5W/m.K.
Identifier: CFE0006537 (IID), ucf:51321 (fedora)
Note(s): 2016-05-01
Ph.D.
Engineering and Computer Science, Electrical Engineering and Computer Engineering
Doctoral
This record was generated from author submitted information.
Subject(s): Thermoelectric -- Infrared -- uncooled -- thermocouple -- detector -- nanowire -- polysilicon
Persistent Link to This Record: http://purl.flvc.org/ucf/fd/CFE0006537
Restrictions on Access: public 2016-11-15
Host Institution: UCF

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