From the early usage of metallic thin films as mirrors tracing back to 2900 BC, to the modern thin film photonic circuits as a mature optical processing platform, and to the growing class of atomically-thin two-dimensional (2D) materials with diverse and tailorable properties, thin film materials have played an important role in the study of and control of light. Their large surface-to-volume ratio makes it feasible to selectively design their properties with a variety of chemical, physical, and optical methods, with their geometry being especially suited for top-down 2D patterning techniques. Electron-beam (E-beam) lithography is currently the state-of-the-art 2D patterning technique. With the capability to create precise and complex features with sizes down the 10 nm scale, E-beam patterning provides one of the most powerful methods to control the nanoscale to microscale structure of thin films for rational control of their electromagnetic environment and properties. Naturally, advances in E-beam patterning of thin film materials can benefit many fields in optics science and engineering. Despite this importance, there are still many unsolved challenges and routes for optimization for E-beam patterning of thin film materials. What is more, E-beam radiation itself can modify the optical properties of some thin film materials, adding an additional degree of freedom for creating desired patterns of materials. Addressing the central role of E-beam patterning to thin film applications, this dissertation describes progress in utilizing E-beam lithography to control optical properties of thin film materials. In Chapter 2, the possibility to use E-beam lithography to change the refractive index of a resist layer for ring resonator tuning is explored. In Chapter 3, the E-beam nanopatterning of layered transition metal dichalcogenides (TMDs) is studied. In Chapter 4, the realization of visible-wavelength topological photonics with improved E-beam lithography methods is discussed. In Chapter 5, application of E-beam lithography for strain and defect control of 2D materials to enable creation of consistent single-photon sources is demonstrated. Finally in appendices, general procedures and precautions of E-beam lithography as well as other topological photonic structures in literature are detailed.

Creator

• Liu, Pufan

DOI

• https://doi.org/10.21985/n2-nyjb-nk02

Subject

• Physics
• Materials Science

Language

• en

Alternate Identifier

• etdadmin_upload_946295
• http://dissertations.umi.com/northwestern:16358

Keyword

• Two-dimensional materials
• Photonic circuits
• Thin film materials
• Topological photonics
• Electron-beam lithography
• Optical materials

Date created

• 2022-01-01

Resource type

• Dissertation

Rights statement

• In Copyright