Guan Yanchao, Ding Ye, Fang Yuqiang, Wang Genwang, Zhao Shouxin, Wang Lianfu, Huang Jingtao, Chen Mengxin, Hao Juanyuan, Xu Chengyan, Zhen Liang, Huang Fuqiang, Li Yang, Yang Lijun
School of Mechatronics Engineering, Harbin Institute of Technology, Harbin, Heilongjiang, 150001, China.
Key Laboratory of Micro-systems and Micro-structures Manufacturing, Ministry of Education, Harbin Institute of Technology, Harbin, Heilongjiang, 150001, China.
Small. 2023 Nov;19(45):e2303654. doi: 10.1002/smll.202303654. Epub 2023 Jul 7.
Laser-driven phase transition of 2D transition metal dichalcogenides has attracted much attention due to its high flexibility and rapidity. However, there are some limitations during the laser irradiation process, especially the unsatisfied surface ablation, the inability of nanoscale phase patterning, and the unexploited physical properties of new phase. In this work, the well-controlled femtosecond (fs) laser-driven transformation from the metallic 2M-WS to the semiconducting 2H-WS is reported, which is confirmed to be a single-crystal to single-crystal transition without layer thinning or obvious ablation. Moreover, a highly ordered 2H/2M nano-periodic phase transition with a resolution of ≈435 nm is achieved, breaking through the existing size bottleneck of laser-driven phase transition, which is attributed to the selective deposition of plasmon energy induced by fs laser. It is also demonstrated that the achieved 2H-WS after laser irradiation contains rich sulfur vacancies, which exhibits highly competitive ammonia gas sensing performance, with a detection limit below 0.1 ppm and a fast response/recovery time of 43/67 s at room temperature. This study provides a new strategy for the preparation of the phase-selective transition homojunction and high-performance applications in electronics.
二维过渡金属二硫属化物的激光驱动相变因其高灵活性和快速性而备受关注。然而，在激光辐照过程中存在一些局限性，特别是表面烧蚀不理想、无法进行纳米级相图案化以及新相的物理性质未被开发利用。在这项工作中，报道了通过精确控制的飞秒（fs）激光驱动金属性2M-WS向半导体性2H-WS的转变，证实这是一种单晶到单晶的转变，没有层变薄或明显的烧蚀。此外，实现了分辨率约为435 nm的高度有序的2H/2M纳米周期性相变，突破了现有激光驱动相变的尺寸瓶颈，这归因于飞秒激光诱导的等离子体能量的选择性沉积。还证明了激光辐照后得到的2H-WS含有丰富的硫空位，其表现出极具竞争力的氨气传感性能，室温下检测限低于0.1 ppm，响应/恢复时间快速，分别为43/67 s。本研究为制备相选择性转变同质结以及电子学中的高性能应用提供了一种新策略。
