title: Electrically Driven Light Emission from Carbon Nanotubes with Quantum Defects
Creators: name: Li, Min-Ken
Publisher: name: UNSPECIFIED
Year: 2024

description: In the modern era, with the high demand for energy-efficient, high-speed, and secure data transmission and information processing, photonic technology has emerged as one of the key players. To further advance in the realm of photonic quantum technologies, single-photon sources are one of the indispensable building blocks. Naturally, single-walled carbon nanotubes (SWCNTs) with sp3 quantum defects, which have attracted great attention in sensing and imaging applications, are of particular interest due to their potential realization as quantum light emitters owing to the superior emission efficiency and the single-photon emission nature in the near-infrared regime. This thesis delves into the exploration of electroluminescence characteristics and the development of an on-chip electrical-driven quantum-light source in the telecom band. The central focus involves the integration of SWCNTs with sp3 quantum defects in a field-effect transistor configuration.
At first, the electrical-driven defect-induced light emission of SWCNTs functionalized with dichlorobenzene molecules is presented. The introduction of sp3 quantum defects forms deep potential traps that facilitate the localization of excitons and govern the optical properties. Gate-dependent defect-state emission lines are assigned as localized excitons/trions based on the correlation of electrical transport and electroluminescence measurements. The unconventional equidistant satellite peaks between intrinsic and defect-state emission lines at cryogenic temperatures can be associated with phonon-mediated hot-exciton electroluminescence. The comparison between the electrostatic gating electroluminescence and the chemical doping photoluminescence of SWCNTs reveals the potential complexity of optical transition identification.
Before photon correlation measurements of defect-state electroluminescence, the superconducting single-photon detectors, a crucial component in the Hanbury Brown and Twiss (HBT) experimental setup, are characterized, and the time resolution limitation and internal time delay of the system are determined. Subsequently, the first demonstration of single-photon emission by coupling either excitonic or trionic defect-state electroluminescence from functionalized (7, 5) SWCNTs into the HBT setup at 77 K is achieved. The interplay between the electrical power and the emission wavelength with the photon antibunching behavior is explored, and limitations of the current system from advancing into more controllable and accessible single-photon emitters, even for room temperature operation, are emphasized. 
Finally, the proposed resolutions of low-loss heterogeneous integration of electrical control on-chip nanoemitters for the development of hybrid integrated photonic circuits are discussed. Full dynamic control of electroluminescent (9, 8) SWCNTs as a result of the site-selective coupling into a cross-bar Si3N4 photonic crystal cavity device nanocrystalline graphene (NCG) electrodes, which avoids compromising on the optical loss, is presented. Additionally, the NCG strip device within the cavity region functions as an incandescent emitter and is exhibited as a candidate for effective Local Density of States probing. The study provides a versatile and scalable approach for photonic applications in the telecom band.