Electrical and Computer Engineering Department, Auburn University, Auburn, Alabama 36849, United States.
ACS Nano. 2023 Jul 11;17(13):12519-12529. doi: 10.1021/acsnano.3c02280. Epub 2023 Jun 20.
Understanding and controlling the growth evolution of atomically thin monolayer two-dimensional (2D) materials such as transition metal dichalcogenides (TMDCs) are vital for next-generation 2D electronics and optoelectronic devices. However, their growth kinetics are not fully observed or well understood due to the bottlenecks associated with the existing synthesis methods. This study demonstrates the time-resolved and ultrafast growth of 2D materials by a laser-based synthesis approach that enables the rapid initiation and termination of the vaporization process during crystal growth. The use of stoichiometric powder (e.g., WSe) minimizes the complex chemistry during the vaporization and growth process, allowing rapid initiation/termination control over the generated flux. An extensive set of experiments is performed to understand the growth evolution, achieving subsecond growth as low as 10 ms along with a 100 μm/s growth rate on a noncatalytic substrate such as Si/SiO. Overall, this study allows us to observe and understand the 2D crystal evolution and growth kinetics with time-resolved and subsecond time scales.
理解和控制原子层薄的二维（2D）材料（如过渡金属二卤化物（TMDC））的生长演化对于下一代 2D 电子和光电子器件至关重要。然而，由于与现有合成方法相关的瓶颈，它们的生长动力学尚未完全观察到或很好地理解。本研究通过基于激光的合成方法展示了 2D 材料的时间分辨和超快生长，该方法可在晶体生长过程中快速启动和终止蒸发过程。使用化学计量粉末（例如，WSe）可最大程度地减少蒸发和生长过程中的复杂化学过程，从而可以快速启动/终止对生成通量的控制。进行了大量实验来了解生长演化，从而在非催化衬底（例如 Si/SiO）上实现了低至 10ms 的亚秒级生长以及 100μm/s 的生长速率。总体而言，这项研究使我们能够观察和理解 2D 晶体的演化和生长动力学，时间分辨率达到亚秒级。
