Opportunities in electrically tunable 2D materials beyond graphene: Recent progress and future outlook

Abstract

The interest in two-dimensional and layered materials continues to expand, driven by the compelling properties of individual atomic layers that can be stacked and/or twisted into synthetic heterostructures. The plethora of electronic properties as well as the emergence of many different quasiparticles, including plasmons, polaritons, trions and excitons with large, tunable binding energies that all can be controlled and modulated through electrical means has given rise to many device applications. In addition, these materials exhibit both room-temperature spin and valley polarization, magnetism, superconductivity, piezoelectricity that are intricately dependent on the composition, crystal structure, stacking, twist angle, layer number and phases of these materials. Initial results on graphene exfoliated from single bulk crystals motivated the development of wide-area, high purity synthesis and heterojunctions with atomically clean interfaces. Now by opening this design space to new synthetic two-dimensional materials "beyond graphene", it is possible to explore uncharted opportunities in designing novel heterostructures for electrical tunable devices. To fully reveal the emerging functionalities and opportunities of these atomically thin materials in practical applications, this review highlights several representative and noteworthy research directions in the use of electrical means to tune these aforementioned physical and structural properties, with an emphasis on discussing major applications of beyond graphene 2D materials in tunable devices in the past few years and an outlook of what is to come in the next decade.

Room-Temperature Oxygen Transport in Nanothin BixOySez Enables Precision Modulation of 2D Materials

“…Our findings indicate that oxygen diffuses very quickly through Bi x O y Se z near room temperature under laser exposure (2.61e-18 m 2 s –1 ), , raising the prospect that it could advance low-temperature SOFC technology and improve syngas production. As an additional application, our work suggests that Bi x O y Se z oxygen transport facilitates the precise manipulation of 2D material properties on the sub-micrometer scale, raising the possibility for a host of spatially selective and tunable properties, including long-lived interlayer excitons, magnetism, and ferroelectricity …”

Study on the relationship between carrier mobility and nonlinear optical characteristics of Sb2Te3–Bi2Te3 lateral heterostructure materials and its applications in fiber lasers

“…Varieties of two-dimensional (2D) materials have emerged successively and stood out in ultrafast optical devices such as photodetectors, optical modulators, all-optical switches and pulse lasers since the discovery of graphene. [1][2][3] But different materials have their characteristics, which cannot simultaneously satisfy all of the optical devices' performance requirements. So there is still much room for improving the properties of 2D materials.…”

Superfluid drag between excitonic polaritons and superconducting electron gas

“…Modern two-dimensional materials and heterostructures [25,26] provide a prospective platform for realization of drag effects. Hybrid Bose-Fermi systems with polaronic and drag effects induced by electron-exciton and electron-polariton interactions are especially interesting in this context [27][28][29][30][31].…”