Optimization of Defects in Monolayer MoS2 via Femtosecond Laser Annealing

In recent years, two-dimensional materials have emerged as a hot research area for semiconductor development and related technologies, paving the way for new directions and possibilities. Among these materials, transition metal dichalcogenides (TMDs) are particularly promising candidates for integrated circuits due to their highly suitable band gap sizes, especially in the context of field-effect transistors (FETs). In the realm of TMDs, molybdenum disulfide (MoS2) and tungsten diselenide (WSe2) have become potential channel materials. However, challenges such as damage, crystallization defects, and imaging issues during the preparation of 2D materials can lead to issues like poor conductivity, inadequate luminescence, instability, and leakage currents. To tackle these challenges, this study focuses on monolayer MoS2 among 2D materials, employing femtosecond laser pulse annealing to rapidly anneal crystals that are defective or damaged. This technique aims to optimize the crystal structure by addressing any defects that may arise during the growth process. Photoluminescence (PL) and Raman spectroscopy serve as detection systems in this research, used to examine the changes in 2D materials before and after annealing, providing valuable insights into their quality and structural integrity. This novel femtosecond pulse annealing technique greatly aids in the fabrication of 3D integrated circuits, as many materials used in 3D IC are two-dimensional. By replacing traditional thermal annealing techniques with femtosecond laser pulse annealing, this method not only eliminates the thermal effects and time-consuming nature associated with conventional annealing, but also harnesses concentrated pulsed laser to achieve rapid thermal processing. This approach effectively suppresses surface defects and enhances characteristics such as conductivity, luminescence, and stability, making it a powerful advancement in next-generation semiconductor technology.