| dc.description.abstract | In recent years, two-dimensional (2D) materials have garnered significant attention and research interest due to their exceptional material properties, including atomic layer thickness, high mobility at reduced dimensions, and tunable band structures. These attributes position 2D materials as promising candidates for next-generation semiconductor technologies. Among these materials, molybdenum disulfide (MoS2) within the transition metal dichalcogenides (TMDs) group has been extensively studied. MoS2 exhibits high mechanical strength, excellent thermal stability, and high carrier mobility, making it highly suitable for applications in photodetection, logic circuits, and high-frequency communications.
Monolayer MoS2 features a semiconductor bandgap of approximately 1.85 eV and can be synthesized into high-quality, large-area, and uniform continuous films through chemical vapor deposition (CVD). This capability enhances its prospects in the semiconductor industry. Traditionally, sapphire substrates have been employed for MoS2 synthesis due to the crystal lattice matching mechanism. However, subsequent processes necessitate the transfer of the MoS2 layer from the sapphire substrate to target substrates such as silicon dioxide (SiO2) or silicon nitride (Si3N4). This transfer introduces numerous defects, including polymer residues, wrinkles, and cracks, which degrade the material′s electrical properties. Consequently, synthesizing MoS2 directly on insulating substrates is of significant importance. Traditional CVD methods have limitations, such as uncontrollable growth locations and non-uniform material sizes.
Therefore, in this study, we propose a highly controllable crystal growth method using gold as a heterogeneous nucleation site. By exploiting differences in reaction energy barriers, we can grow monolayer MoS2 crystals with a size of 10 micrometers at predetermined nucleation sites on a SiO2 substrate. Photoluminescence (PL) analysis reveals that these crystals exhibit high crystallinity with a full width at half maximum (FWHM) of 61 meV. Additionally, Raman spectroscopy and PL mapping indicate that these single crystals are monolayers with high uniformity and crystallinity. Using this method, we can achieve uniform-sized and large-area single-crystal MoS2 arrays (50×50), subsequently fabricating gate, drain, and source electrodes to produce two-dimensional field-effect transistors (FETs). This method avoids transfer and transistor area etching steps, is compatible with current semiconductor processes, and significantly reduces process complexity and cost. | en_US |