Vapor-phase growth techniques such as chemical vapor deposition (CVD) and molecular beam epitaxy (MBE) have demonstrated their potential in producing two-dimensional (2D) superlattices, which are of great interest for advanced electronic, spintronic, and quantum applications. These methods allow precise control over material deposition and interface sharpness, facilitating the creation of well-defined superlattices with unique properties. However, they face significant challenges, limiting their scalability and efficiency. Key issues include restricted material diversity, competition between vertical and lateral nucleation during growth, alloying effects such as sulfur-selenium exchange, and low tolerance to thermally induced degradation. Additionally, the reliance on ultra-high vacuum environments, stringent system requirements, and lengthy growth durations—often extending to hundreds of hours—further hinder their widespread adoption and scalability.To address these limitations, this dissertation explored alternative synthesis strategies, focusing on bottom-up approaches such as ion-exchange intercalation, chemical intercalation and exfoliation-assembly. These methods leverage the unique properties of 2D atomic crystals (2DACs), such as transition metal dichalcogenides (TMDs), to create highly ordered atomic superlattices and hybrid superlattices. The ion-exchange intercalation technique enables the incorporation of functional cations, Cu⁺, Ag⁺, Mn²⁺, Fe²⁺, Co²⁺, Ni²⁺, Gd3+ and Eu3+ into a broad range of 2DACs such as MoS2, MoSe2, MoTe2, WS2, WSe2, WTe2, SnSe2, and In2Se3. This process produces atomic superlattices with remarkable tunability in their electronic and magnetic properties. These materials exhibit robust room-temperature ferromagnetism, with tunable magnetic behavior dependent on cation concentration, as well as a unique coexistence of ferromagnetism and superconductivity, exemplified by CoNbSe2. And the precise control of Cu atomic doping in Bi2Se3 can be achieved through one-pot chemical synthesis, which showed intercalation induced superconductivity at certain ratios.
In addition, hybrid superlattices were synthesized using direct chemical intercalation and exfoliation-assembly techniques. Direct intercalation enabled the incorporation of chiral molecules such as S-MBA and R-MBA into TMDs, while the exfoliation-assembly method allowed the systematic construction of MoS2 monolayer superlattices assembled with functional molecules, including amino acids, polymers, and coordination complexes. These hybrid structures demonstrated several novel phenomena, including chiral molecule induced chirality, enhanced superconductivity through interlayer engineering, and charge-transfer-driven magnetism. For instance, the introduction of chiral molecules into TaS2 superlattices led to unique optical responses, while interlayer engineering using amine molecules enhanced the superconductivity of TaS2. The assembly of MoS2 monolayers with Co(en)3Cl3 complexes demonstrated charge-transfer-driven magnetic ordering, providing insights into the coupling between electronic and magnetic properties at the atomic scale.
Overall, this thesis advanced versatile, scalable strategies for engineering 2D-based materials with tailored functionalities, effectively overcoming the limitations of traditional vapor-phase growth methods. By integrating novel intercalation and assembly techniques, this research establishes a robust platform for the systematic exploration of 2DACs, paving the way for breakthroughs in electronic, spintronic, and quantum technologies.