Two-dimensional dielectric nanosheets: Novel nanoelectronics from nanocrystal building blocks

Two-dimensional (2D) nanosheets, which possess atomic or molecular thickness and infinite planar lengths, are regarded as the thinnest functional nanomaterials. The recent development of methods for manipulating graphene (carbon nanosheet) has provided new possibilities and applications for 2D systems; many amazing functionalities such as high electron mobility and quantum Hall effects have been discovered. However, graphene is a conductor, and electronic technology also requires insulators, which are essential for many devices such as memories, capacitors, and gate dielectrics. Along with graphene, inorganic nanosheets have thus increasingly attracted fundamental research interest because they have the potential to be used as dielectric alternatives in next-generation nanoelectronics. Here, we review the progress made in the properties of dielectric nanosheets, highlighting emerging functionalities in electronic applications. We also present a perspective on the advantages offered by this class of materials for future nanoelectronics. 2D inorganic nanosheets are interesting dielectric building blocks that can be used as a dielectric analogue of graphene. Layer-by-layer engineering approach of these nanosheets promises unique possibilities to design thin-film device architectures such as capacitors, gate dielectrics, transistors, and artificial ferroelectrics. Trends and recent progress in this class of materials are highlighted and provide a perspective for future nanoelectronics.