Ultrasonic delamination based adhesion testing for high-throughput assembly of van der Waals heterostructures
Ultrasonic delamination based adhesion testing for high-throughput assembly of van der Waals heterostructures
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DOI：
10.1063/5.0126446
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发表时间：
2022-10
影响因子：
3.2
通讯作者：
Tara Peña;Jewel Holt;Arfan Sewaket;Stephen M. Wu
中科院分区：
文献类型：
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作者：
Tara Peña;Jewel Holt;Arfan Sewaket;Stephen M. Wu
组装成范德华 (vdW) 异质结构的二维 (2D) 材料包含机械、光学和电气特性的无限组合，可用于潜在的设备应用。至关重要的是，这些结构需要控制界面粘附力以实现其构造，并且具有足够的完整性以在集成时在工业制造过程中生存。在这里，我们使用超声波分层阈值测试快速确定各种剥离的二维材料在传统 SiO2/Si 基板上的粘合质量。该测试使我们能够根据在超声波浴中存活固定时间的二维薄片的面积百分比快速推断相对基材粘附力，从而控制产生高粘附力或差粘附力的工艺参数。我们利用这种粘附力控制来优化 vdW 异质结构组装过程，其中我们表明，相对于彼此具有高或低基底粘附力的样品可以选择性地用于构建高通量 vdW 堆叠。我们不是通过恒定的 2D 基材粘附力来调整聚合物印模对 2D 材料的粘附力，而是通过对 2D 材料的恒定印模粘附力来调整 2D 基材粘附力。聚合物印模可以重复使用，无需任何聚合物熔化步骤，从而避免高温（<120°C）并允许高通量生产。我们表明，该过程可用于在 SiO2/Si 上创建高质量的二维扭曲双层石墨烯，并通过原子力显微镜和拉曼光谱图进行表征，以及 h-BN/SiO2/Si 上的低角度扭曲双层 WSe2，其中我们展示了使用倾斜角度相关扫描电子显微镜进行莫尔重构的直接实空间可视化。
Two-dimensional (2D) materials assembled into van der Waals (vdW) heterostructures contain unlimited combinations of mechanical, optical, and electrical properties that can be harnessed for potential device applications. Critically, these structures require control over interfacial adhesion for enabling their construction and have enough integrity to survive industrial fabrication processes upon their integration. Here, we promptly determine the adhesion quality of various exfoliated 2D materials on conventional SiO2/Si substrates using ultrasonic delamination threshold testing. This test allows us to quickly infer relative substrate adhesion based on the percent area of 2D flakes that survive a fixed time in an ultrasonic bath, allowing for control over process parameters that yield high or poor adhesion. We leverage this control of adhesion to optimize the vdW heterostructure assembly process, where we show that samples with high or low substrate adhesion relative to each other can be used selectively to construct high-throughput vdW stacks. Instead of tuning the adhesion of polymer stamps to 2D materials with constant 2D-substrate adhesion, we tune the 2D-substrate adhesion with constant stamp adhesion to 2D materials. The polymer stamps may be reused without any polymer melting steps, thus avoiding high temperatures (<120 °C) and allowing for high-throughput production. We show that this procedure can be used to create high-quality 2D twisted bilayer graphene on SiO2/Si, characterized with atomic force microscopy and Raman spectroscopic mapping, as well as low-angle twisted bilayer WSe2 on h-BN/SiO2/Si, where we show direct real-space visualization of moiré reconstruction with tilt-angle dependent scanning electron microscopy.