Date of Graduation

5-2024

Document Type

Thesis

Degree Name

Master of Science in Materials Engineering (MS)

Degree Level

Graduate

Department

Materials Science & Engineering

Advisor/Mentor

Churchill, Hugh O.H.

Committee Member

El-Shenawee, Magda O.

Second Committee Member

Leftwich, Matthew B.

Third Committee Member

Coridan, Robert H.

Keywords

Black Phosphorus; Hall bars; Low dimensional materials; Photoconductive antenna; Terahertz

Abstract

Advancements in terahertz (THz) imaging systems, particularly for applications like post-surgical analysis of breast cancer, have led to the exploration of novel materials such as black phosphorus as the active material for a THz photoconductive antenna (PCA). This thesis, motivated by innovative techniques developed at the University of Arkansas, investigates the potential of black phosphorus as a material to enhance the performance of THz PCAs, focusing on generation efficiency and bandwidth. Previous implementations of BP as THz emitters have shown limitations, highlighting the need for thorough material characterization and optimized fabrication processes. Therefore, we adopted a dual-phase approach to this project. The initial phase involved evaluating black phosphorus supplied by various vendors to identify the most suitable source based on carrier density and mobility, essential for high-performance THz PCAs. The investigation identified HQ Graphene as the only vendor meeting the material standards for advancing BP PCA fabrication, thereby narrowing the focus for subsequent antenna development efforts. The second phase aimed to fabricate and assess the THz PCAs utilizing the selected black phosphorus. These antennas did not meet the efficiency levels of current standard emitters, with observed deficiencies in pulse peak amplitude and emission delay. This suggests a critical look into the scattering centers and carrier concentration, pivotal for optimizing the energy conversion through carrier recombination in THz generation.This thesis contributes to the ongoing dialogue on material innovation for THz antenna technology by providing a detailed investigation of the fabrication challenges and characterization of black phosphorus as a promising, yet demanding, material for future terahertz photoconductive antenna applications.

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