A versatile sample fabrication method for ultrafast electron diffraction.
A versatile sample fabrication method for ultrafast electron diffraction.
复制标题
DOI：
10.1016/j.ultramic.2021.113389
复制
发表时间：
2021-11-01
期刊：
影响因子：
2.2
通讯作者：
Gedik, Nuh
中科院分区：
文献类型：
--
作者：
Bie, Ya-Qing;Zong, Alfred;Gedik, Nuh
固态系统中非平衡现象的探索不可或缺的是飞秒激光脉冲光激发后晶格运动的研究。在过去的二十年里，超快电子衍射（UED）在这方面发挥了关键作用。尽管在仪器开发方面取得了显着进展，但该技术仍然受到苛刻的样品制备过程的考验，其中通常需要大横向尺寸的单晶。在这项工作中，我们描述了一种有效的，多功能的方法，产生高质量的，横向延伸（≥ 100米），薄（≤ 50纳米）的非晶薄膜的氮化硅窗口的单晶。它适用于大多数可剥离材料，包括那些在环境条件下反应，并承诺清洁，平坦的表面。除了自然延伸到制造货车德瓦尔斯异质结构，我们的方法也可以应用到下一代UED，使额外的控制样品参数，如静电门控和激发的局部增强太赫兹场。我们的工作显着扩大了UED研究的样品类型，也发现在其他时间分辨技术，如阿秒极紫外吸收光谱的应用。因此，这种方法提供了进一步的机会，探索光致跃迁和发现新的物质状态的平衡。
Integral to the exploration of nonequilibrium phenomena in solid-state systems is the study of lattice motion after photoexcitation by a femtosecond laser pulse. For the past two decades, ultrafast electron diffraction (UED) has played a critical role in this regard. Despite remarkable progress in instrumental development, this technique is still bottlenecked by a demanding sample preparation process, where ultrathin single crystals of large lateral size are typically required. In this work, we describe an efficient, versatile method that yields high-quality, laterally extended (≥ 100m), and thin (≤ 50nm) single crystals on amorphous films of Si3N4 windows. It applies to most exfoliable materials, including those reactive in ambient conditions, and promises clean, flat surfaces. Besides the natural extension to fabricating van der Waals heterostructures, our method can also be applied to future-generation UED that enables additional control of sample parameters, such as electrostatic gating and excitation by a locally enhanced terahertz field. Our work significantly expands the type of samples for UED studies and also finds application in other time-resolved techniques such as attosecond extreme-ultraviolet absorption spectroscopy. This method hence provides further opportunities to explore photoinduced transitions and to discover novel states of matter out of equilibrium.