Borophenes: monolayer, bilayer and heterostructures

Borophene, a two-dimensional material with excellent mechanical, electronic, optical, thermal and superconducting properties, has attracted significant attention since its synthesis in 2015 due to its potential applications in electronics, energy storage, transport, catalysis, plasmonics, superconductivity, sensors, and others. Borophene's unique properties, such as 2D metallic properties, ideal flexibility and strength, antiferromagnetism, and excellent gas-sensing properties, have made it a promising material for use in various fields. In particular, the strength and flexibility of borophene make it an ideal candidate for the design of various devices, and its large surface zone and exceptional conductance make it suitable for use in energy storage devices and electrode materials. While borophene is a relatively new material, its synthesis has advanced significantly in recent years. This review introduces several monolayer borophenes synthesized by molecular beam epitaxy on metal substrates, followed by a discussion of two successfully synthesized bilayer borophenes and four borophene-based heterostructures. These developments have opened new possibilities for the integration of borophene into nanodevice applications.