Integration of 2-D Transition Metal Dichalcogenides (TMDs) in Quantum Devices

Abstract

Quantum devices require materials with stable electronic, optical, and superconducting properties that can be integrated into nanoscale structures. Two-dimensional transition metal dichalcogenides (TMDs) are promising for this purpose because of their strong light-matter interaction, spin-orbit coupling, superconductivity, and compatibility with van der Waals heterostructures. However, their integration into quantum devices is still limited by material quality, fabrication reproducibility, defect control, and substrate-dependent behavior. This thesis studies 2-D TMDs for quantum technologies through two systems: superconducting NbSe2 nanowires and functionalized WS2 for localized quantum light emission. NbSe2 nanowires were fabricated on Si/SiO2 substrate using UV optical lithography and converted by chemical vapor deposition (CVD). Gas-precursor single-zone CVD and powder-precursor two-zone CVD processes were compared using Raman spectroscopy, electrical transport, X-ray photoelectron spectroscopy, and cryogenic superconductivity measurements. In the second part, spatially localized emitters in WS2 were studied through photo-induced covalent functionalization with iodobenzene using a custom optical setup. Mechanically exfoliated WS2, MOCVD-grown WS2 on Si/SiO2, and MOCVD-grown WS2 on hBN were compared. The results show that optimized NbSe2 synthesis can produce superconducting films, while controlled WS2 functionalization activates localized optical states.