Publication Date

2024

Document Type

Dissertation/Thesis

First Advisor

Xiao, Zhili

Degree Name

Ph.D. (Doctor of Philosophy)

Legacy Department

Department of Physics

Abstract

Superconducting nanowire devices fit a broad spectrum of applications, including particle detection and quantum computing, and their expanding use across various fields highlights their role in the hybridization of superconducting and conventional semiconductor electronics. Despite their potential, the low signal output of these devices raises challenges in scalability and integration, particularly in applications for nuclear and high-energy physics, where resilience in magnetic fields is becoming a critical optimization factor. The superconducting nanowire cryotron (nTron) addresses these issues by providing operational gain and logic switching in superconducting nanowire circuits, demonstrating adaptability to multiple materials. This dissertation focuses on modifying the conventional geometry of nTrons by including parallel current-carrying channels, aimed at improving the device’s magnetic field performance. The common challenge in nTron devices is to maintain efficient operation under varying magnetic field conditions. Here we show that the adaptation of parallel channel configurations leads to an enhanced gate signal sensitivity, an increase in operational gain, and a reduction in the impact of superconducting vortices on nTron operation within magnetic fields up to 1 T. Contrary to conventional designs that are constrained by their effective channel width, the parallel nanowire channels permits larger nTron cross-sections, further bolstering the device’s magnetic field resilience while improving electro-thermal recovery times due to reduced local inductance. This advancement in nTron design not only augments its functionality in magnetic fields but also broadens its applicability in technological environments, offering a simple design alternative to existing nTron devices.

Furthermore, I expand on the ion beam assisted sputtering (IBAS) technique, originally developed for niobium nitride (NbN), to explore its effects on titanium nitride (TiN) synthesis, which is a material with promising prospects for nTrons and other superconducting circuitry. The IBAS technique has demonstrated an enhancement in nominal critical temperature without noticeable variation in the lattice structure whilst enabling a controllable and optimized growth method. Additionally, we explore the behavior of superconducting Tc in ultra-thin films (< 100 nm). Trends in films grown at high nitrogen concentrations follow predictions of mean-field theory in disordered films and show suppression of superconducting Tc due to geometric confinement effects, while films grown at low nitrogen concentrations strongly deviate from the theoretical models.

Extent

152 pages

Language

en

Publisher

Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

Media Type

Text

Download

Share

COinS