Study on structure control of two-dimensional materials ($MoS_2$, MXene) and development of its applications

Abstract

Two-dimensional (2D) materials have been attracted abundant attentions as a promising new materials with their extraordinary property, which could not be represented in bulk state. The property of 2D materials remarkably depends on its structure. Therefore, the method to control structure is highly demand for a novel applications. We tried to develop the structure control method with self-assembly process and unique patterning to optimize properties of transition metal dichacogenide (TMD) and MXene based device. Self-assembly at liquid-air interface could finely control the thickness of TMD thin film within atomic scale. The formed TMD thin film has a high coverage with single layer geometry, which could not be demonstrated from conventional solution-based thin film formation process. Interestingly, this interfacial self-assembly method could be further applied into MXene material. Nanoscale thickness of MXene thin film demonstrates the high electromagnetic interface (EMI) shielding effect comparing with other nanomaterials. Our MXene thin film could be modeled for studying intrinsic properties such as conductivity, transmittance, and EMI shielding effect. In addition, we demonstrated the simple method to form 3D porous structure of 2D MXene via spontaneous gelation. By simply adding MXene solution into Zn plate, MXene hydrogel was readily achieved on Zn plate surface. Furthermore, unique patterning of TMD highly demands for the advance application. We tried to apply block copolymer (BCP) nanotemplate for forming nanomesh, nanodot, and nanowire of TMDs. With proper treatment for self-assembly of BCP and selective etching of one part of BCP (PMMA), remained PS part could be nanotemplates. We deposited desired seed metal from e-beam evaporator and then, sulfurization process demonstrated nanostructured TMD after lift-off process.