Engineering and Activating Room-Temperature Quantum Light Emission in Two-Dimensional Materials With Nano-Programmable Strain

• Main Author: Yanev, Emanuil S
• Format: Dissertation
• Language: English
• Published: ProQuest Dissertations & Theses 01-01-2024
• Subjects: Condensed matter physics; Materials science; Mechanical engineering; Nanotechnology; Quantum physics
• ISBN: 9798383234907

Micro– and subsequently nano–scale fabrication techniques have reshaped our world more drastically than almost any other development of the last half-century. Spurred by the invention of the transistor at Bell Labs in 1947, monolithic integrated circuits—or microchips in the colloquial lexicon— were developed in ’59, kickstarting the modern digital age as we know it. More recently, the maturation of classical computing technology and significant advancements in materials science have led to a boom of interest in and progress by the quantum sector on both computation and communication fronts. The explosive growth currently underway in the field of quantum information science (QIS) marks the dawning of a new age, which will undoubtedly transform our world in ways we have yet to imagine. This dissertation seeks to leverage advanced nanofabrication approaches, atomically thin materials, and state of the art microscopy techniques to develop room-temperature single photon sources for QIS applications. A basic overview of 2D materials is provided in Chapter 1. Particular emphasis is placed on the optical properties of tungsten diselenide (WSe2), which is followed by a brief discussion of quantum emitters in 2D and other material systems. Chapter 2 describes the scanning near-field optical microscopy (SNOM) technique we use to investigate the photoluminescence (PL) response of strained WSe2 with resolution well below the classical diffraction limit. The third chapter is dedicated to the various fabrication methods explored and developed to produce the plasmonic substrates necessary for near-field optical studies. The first section focuses on the creation of extremely flat metallic surfaces, while the second deals with extremely sharp metallic stressors. These two platforms enable the investigations of nanobubbles—touched upon in Chapter 2—and nanowrinkles, which are the subject of discussion in Chapter 4. The strain confinement provided by these wrinkles leads to highly localized quantum dot-like states that exhibit excitation power saturation at room temperature. Together, these studies lay the groundwork for achieving high-temperature quantum emission in atomically thin semiconducting van der Waals materials.