Methods for synthesis of ultra-high temperature carbons and carbides

Stritt, Jaspa 2024. Methods for synthesis of ultra-high temperature carbons and carbides. PhD Thesis, Cardiff University. Item availability restricted.

Preview	PDF - Accepted Post-Print Version Available under License Creative Commons Attribution Non-commercial No Derivatives. Download (67MB) | Preview
	PDF (Cardiff University Electronic Publication Form) - Other Restricted to Repository staff only Download (185kB)

Abstract

Using Micro-Electrical Mechanical Systems (MEMS) fabrication methods, others have developed and manufactured silicon-based infrared (IR) micro-transmitters based on the principles of Joule heating and Planck radiation. However, due to the temperature constraints of silicon (1414°C), the maximum intensity and peak wavelength of the emitted black-body radiation are significantly limited. With the advent of processes developed to create MEMS hotplates from a single layer of material, the potential to utilize materials with ultra-high temperature resilience opens exciting opportunities for fabricating highly tunable broadband emitters centered in the near-IR with unprecedentedly high intensities. This thesis investigates the potential of using glass-like carbon and hafnium carbide—two materials with temperature resilience above 3000K within traditional photolithography for the eventual fabrication of MEMS hotplates. Chapters 3 and 4 explore the synthesis process of glass-like carbon thin films via pyrolysis from SU-8 3005 photoresist, using ex-situ microwave dielectric spectroscopy techniques and in-situ X-ray photo-electron spectroscopy to understand the structural and compositional changes during synthesis. Through these studies, the mechanisms by which long-range conductivity and a conducting sp2 carbon network emerge are identified, with clear temperature-dependent transitions shown. Meanwhile, Chapter 5 explores the unprecedented possibility of hafnium carbide (HfC) growth on silicon via chemical vapor deposition, utilizing seed nucleation techniques proven effective in poly-crystalline diamond growth. A milling process is presented for modifying the zeta potential of HfC from negative to positive, enabling a potential method for HfC chemical vapor deposition on silicon.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Schools > Physics and Astronomy
Subjects:	Q Science > QC Physics
Uncontrolled Keywords:	Glass-like Carbon; Hafnium Carbide; MEMS; Infrared Emitters; Hotplates; SU-8 Pyrolysis; Dielectric Spectroscopy; X-ray Photoelectron Spectroscopy
Funders:	Cardiff University PSE College
Date of First Compliant Deposit:	22 May 2025
Last Modified:	22 May 2025 15:23
URI:	https://orca.cardiff.ac.uk/id/eprint/178425

Actions (repository staff only)

Edit Item