Epitaxy Growth Of Bi-Layered 2D Semiconductors with Wafer-Scale Crystallinity on Non-Rigid Substrates

Research in electronic nanomaterials has evolved remarkably over the decades. Traditionally dominated by studies of nanocrystals/fullerenes and nanowires/nanotubes, there is now a burgeoning interest in two-dimensional (2D) atomically thin films. Such materials present immense potential and practicality for unconventional soft electronics, i.e., foldable, bendable, and twistable to irregular surfaces. To this end, prevailing strategies typically hinge on transferring 2D thin films onto a pre-stretched elastomer substrate, tuning of material thickness, blending the 2D semiconductors with plasticizing agents, or the utilization of wavy or serpentine structures and patterning of elastomeric substrates of variable stiffness. While soft polymeric substrates often lead to polycrystalline or amorphous results due to their inherent limitations, crystalline substrates that are innately rigid offer the lattice alignment needed for epitaxy growth of single-crystal 2D materials. Thus, achieving direct epitaxy growth of single-crystal 2D materials on non-rigid substrates presents a dichotomy between desired electronic and mechanical properties. In this talk, we delve into the direct epitaxy growth of single crystalline 2D materials, particularly in their mono- and bilayer nanoribbon formats, on soft, insulating, or semiconducting substrates that are both bendable and twistable. This discovery significantly broadens the landscape of potential applications, enabling more robust and versatile electronic devices that can conform and adapt to varied form factors without compromising their performance. The synthesis techniques have also seen leaps and bounds in progression, creating twisted heterostructures with unparalleled properties.