Date of Award

2025-12-01

Degree Name

Doctor of Philosophy

Department

Mechanical Engineering

Advisor(s)

Yirong Lin

Abstract

To develop Ga2O3 and TiOₓNᵧ thin films for optical applications, the process–structure–properties relationship was investigated using a comprehensive set of characterization techniques to establish the atomic structure and composition of the films in relation to the deposition conditions. The results provide critical insights into how deposition parameters influence the atomic structure and composition during magnetron sputtering. Furthermore, the correlation between atomic structure and composition with the optical and electrical properties of the films was examined to determine how variations in these factors affect functional performance. Collectively, these findings offer the necessary information to target desirable optical properties for Ga2O3 and TiO?N? through optimization of deposition parameters. For the crystalline RF magnetron co-sputtered Sn:Ga2O3, the optical and electrical properties were assisted by a combination of direct measurements and evaluation of the performance of a simple MSM photodetector fabricated from the films. The result shows the deposition technique used is a viable method of producing Ga2O3 thin films with suitable optical properties for Solar-Blind deep UV photodetection. From the characterization of the photoresponse of the detector along with the in-depth atomic structure characterization identified how the sputtering process could be refined to process films improved photoresponse. The pulsed DC sputtering of amorphous Ga2O3 using a ceramic target showed that high quality films of ultra-wide bandgap materials could be deposited using this technique. The reactive sputtered films have optical properties similar to the crystalline phase and the nonreactive samples displayed strong optical absorption with the formation of Ga metal within the amorphous matrix. TiO?N? proved to possess unique combination of high electoral conductivity along with strong optical absorption in amorphous film. The optical and electrical properties of these films are highly sensitive to changes in the O/N ratio, enabling the tuning and optimization of the conductive amorphous film to meet the requirements of high-performance optical devices.

Language

en

Provenance

Received from ProQuest

File Size

161 p.

File Format

application/pdf

Rights Holder

Nathan Christopher Episcopo

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