Advances in two-dimensional heterostructures by mono-element intercalation underneath epitaxial graphene

2D magnetic phases of Eu on Ge(110)

“…High chemical reactivity of the Eu phases presents a significant problem – the systems are oxidized by small amounts of oxygen, similar to Eu/Si(001). 35 Therefore, ex situ experiments demand protection of the Eu/Ge(110) phases. Such a protection can be provided by graphene.…”

“…34 Mono-element intercalation underneath graphene (including Eu) is a well-developed technique. 35 In particular, intercalation of a magnetic metal into the graphene/Ge interface has been suggested as a way to induce large exchange splitting in the π-band of graphene. 36 Below, we provide the results on the synthesis, structure and magnetism of Eu/Ge(110) phases.…”

Construction and physical properties of low-dimensional structures for nanoscale electronic devices

“…The wide range of band gaps in 2D semiconductors from 0.4 to 2.0 eV allows the formation of vdW heterostrucutures with type I (straddling gap), type II (staggered gap), and type III (broken gap) band alignments. 159,160 Compared to conventional quantum wells or superlattices, vdW heterostructures have steep band edges, giving rise to revolutionary possibilities of quantum engineering the transport of charge carriers and excitons. 161 Moreover, vdW heterostructures can be formed by either vertically or laterally stacking 2D semiconductors, enabling the construction of novel proof-of-principle devices.…”

Epitaxial Growth of Monolayer SnSe2 Films on Gd-Intercalated Quasi-Free-Standing Monolayer Graphene with Enhanced Interface Adsorption

“…Graphene, an atomically thin carbon film with a linear electronic band structure and higher carrier mobility, has been extensively studied for its remarkable optical and electronic properties. − The unique sp 2 hybridized orbitals and π-orbitals of graphene constitute its remarkable crystal lattice and electronic structure, which results in tremendous potential in terms of an anomalous quantum hall effect, Klein tunneling, weak antilocalization, and so forth. − Besides, the ultra-flat and chemically inert surface in graphene makes it an ideal substrate for the growth of two-dimensional (2D) films, such as Bi 2 Se 3 , MoSe 2 , WSe 2 , NbSe 2 , and so forth. − However, many 2D films grown on regular epitaxial graphene show a mixture of different thicknesses due to the weak interface adsorption. − In order to improve the advantages of graphene, many efforts have been devoted to modulating the band structure of the epitaxial graphene and reducing its interaction with the substrate. − For example, intercalation is one of the most effective and harmless ways to modulate the electronic properties of epitaxial graphene. , Many fantastic properties of epitaxial graphene can be realized by intercalation depending on the types of intercalated atoms. ,− Importantly, intercalation decouples epitaxial graphene or the buffer layer from the bulk substrate to form quasi-free-standing graphene. , Especially, the Gd atoms intercalated underneath the buffer layer not only decouple graphene from the SiC substrate but also introduce a heavily electronic doping effect and strong correlation effect into graphene . As a result, the intercalation of graphene provides an opportunity for improving the physical and chemical properties of graphene, such as tune the doping of graphene, induce graphene magnetic responses, and increase the spin degree of freedom of the Dirac electrons. , …”

“…19−21 For example, intercalation is one of the most effective and harmless ways to modulate the electronic properties of epitaxial graphene. 22,23 Many fantastic properties of epitaxial graphene can be realized by intercalation depending on the types of intercalated atoms. 19,24−26 Importantly, intercalation decouples epitaxial graphene or the buffer layer from the bulk substrate to form quasi-free-standing graphene.…”