Abstract

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 room temperature. These detectors have been around for many years, however, their performance has been lower than their contesting technologies. A novel high-responsivity uncooled thermoelectric infrared detector is designed, fabricated, and characterized. This detector features a single standalone polysilicon-based thermocouple (without a supporting membrane) covered by an umbrellalike optical-cavity IR absorber. It is proved that the highest responsivity in the developed detectors can be achieved with only one thermocouple. Since the sub-micrometer polysilicon TE wires are the 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 a 20?m x 20?m detector comparable to the performance of detectors used in commercial focal planar arrays. This performance in a compact and manufacturable design elevates the position of thermoelectric IR sensors as a candidate for low-power, high performance, and inexpensive focal planar arrays. The improvement in performance is mostly due to low thermal conductivity of thin polysilicon wires. A feature is designed and fabricated to characterize the thermal conductivity of such a wire and it is shown for the first time that the thermal conductivity of thin polysilicon films can be much lower than that of the bulk. Thermal conductivity of ~110nm LPCVD polysilicon deposited at 620C is measured to be ~3.5W/m.K.

Notes

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Graduation Date

2016

Semester

Spring

Advisor

Abdolvand, Reza

Degree

Doctor of Philosophy (Ph.D.)

College

College of Engineering and Computer Science

Department

Electrical Engineering and Computer Engineering

Degree Program

Electrical Engineering

Format

application/pdf

Identifier

CFE0006537

URL

http://purl.fcla.edu/fcla/etd/CFE0006537

Language

English

Release Date

November 2016

Length of Campus-only Access

None

Access Status

Doctoral Dissertation (Open Access)

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