Hybrid van der Waals Integration through Hydrogel-Mediated Laser Printing

Van der Waals integration for 2D heterostructures is a generalized strategy for assembling various materials into tailored heterostructures without lattice and processing limitations. An effective and reliable transfer medium and method are crucial for successful van der Waals integration. The liquid medium has been widely used for a wet-transfer method, which is a facile and clean transfer but is usually accompanied by poor transfer quality and stability. Here, we report that a structured liquid, such as hydrogel, can be used as an effective transfer medium for the reliable transfer of 2D materials and beyond. The hydrogel-assisted transfer enables cleaner transfers with spatially homogeneous internal strain distribution and exceptional transfer stability. Furthermore, the hydrogel serves as an ideal medium for layer-by-layer laser printing due to its super-fast release rate and transparent nature for the laser beam. We demonstrated that hydrogel-mediated laser printing can be applied to stack various materials beyond 2D materials and realize hybrid van der Waals integration for device fabrication.