Intercalation of insulating materials between epitaxial graphene and the metal substrates is highly demanded to restore the intrinsic properties of graphene,and thus essential for the graphene-based devices.Here we de...Intercalation of insulating materials between epitaxial graphene and the metal substrates is highly demanded to restore the intrinsic properties of graphene,and thus essential for the graphene-based devices.Here we demonstrate a successful solution for the intercalation of hafnium oxide into the interface between full-layer graphene and Ir(111)substrate.We first intercalate hafnium atoms beneath the epitaxial graphene.The intercalation of the hafnium atoms leads to the variation of the graphene moire superstructure periodicity,which is characterized by low-energy electron diffraction(LEED)and lowtemperature scanning tunneling microscopy(LT-STM).Subsequently,we introduce oxygen into the interface,resulting in oxidization of the intercalated hafnium.STM and Raman's characterizations reveal that the intercalated hafnium oxide layer could effectively decouple the graphene from the metallic substrate,while the graphene maintains its high quality.Our work suggests a high-k dielectric layer has been successfully intercalated between high-quality epitaxial graphene and metal substrate,providing a platform for applications of large-scale,high-quality graphene for electronic devices.展开更多
Two-dimensional(2 D) materials provide a platform to exploit the novel physical properties of functional nanodevices.Here, we report on the formation of a new 2 D layered material, a well-ordered monolayer TiTe_2, on ...Two-dimensional(2 D) materials provide a platform to exploit the novel physical properties of functional nanodevices.Here, we report on the formation of a new 2 D layered material, a well-ordered monolayer TiTe_2, on a Au(111) surface by molecular beam epitaxy(MBE). Low-energy electron diffraction(LEED) measurements of the samples indicate that the TiTe_2 film forms(√3 ×√7) superlattice with respect to the Au(111) substrate, which has three different orientations. Scanning tunneling microscopy(STM) measurements clearly show three ordered domains consistent with the LEED patterns.Density functional theory(DFT) calculations further confirm the formation of 2 H-TiTe_2 monolayer on the Au(111) surface with Te as buffer layer. The fabrication of this 2 D layered heterostructure expands 2 D material database, which may bring new physical properties for future applications.展开更多
基金the Ministry of Science and Technology of China(Grant Nos.2018YFA0305800 and2019YFA0308500)the National Natural Science Foundation of China(Grant No.61925111)+2 种基金the Chinese Academy of Sciences(Grant Nos.XDB28000000 and YSBR-003)the Fundamental Research Funds for the Central Universitiesthe CAS Key Laboratory of Vacuum Physics。
文摘Intercalation of insulating materials between epitaxial graphene and the metal substrates is highly demanded to restore the intrinsic properties of graphene,and thus essential for the graphene-based devices.Here we demonstrate a successful solution for the intercalation of hafnium oxide into the interface between full-layer graphene and Ir(111)substrate.We first intercalate hafnium atoms beneath the epitaxial graphene.The intercalation of the hafnium atoms leads to the variation of the graphene moire superstructure periodicity,which is characterized by low-energy electron diffraction(LEED)and lowtemperature scanning tunneling microscopy(LT-STM).Subsequently,we introduce oxygen into the interface,resulting in oxidization of the intercalated hafnium.STM and Raman's characterizations reveal that the intercalated hafnium oxide layer could effectively decouple the graphene from the metallic substrate,while the graphene maintains its high quality.Our work suggests a high-k dielectric layer has been successfully intercalated between high-quality epitaxial graphene and metal substrate,providing a platform for applications of large-scale,high-quality graphene for electronic devices.
基金Project supported by the National Key Research&Development Program of China(Grant Nos.2016YFA0202300 and 2018YFA0305800)the National Natural Science Foundation of China(Grant Nos.61504149,61725107,51572290,and 61622116)+2 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(Grant Nos.XDB30000000 and XDB28000000)the University of Chinese Academy of Sciencesthe CAS Key Laboratory of Vacuum Physics
文摘Two-dimensional(2 D) materials provide a platform to exploit the novel physical properties of functional nanodevices.Here, we report on the formation of a new 2 D layered material, a well-ordered monolayer TiTe_2, on a Au(111) surface by molecular beam epitaxy(MBE). Low-energy electron diffraction(LEED) measurements of the samples indicate that the TiTe_2 film forms(√3 ×√7) superlattice with respect to the Au(111) substrate, which has three different orientations. Scanning tunneling microscopy(STM) measurements clearly show three ordered domains consistent with the LEED patterns.Density functional theory(DFT) calculations further confirm the formation of 2 H-TiTe_2 monolayer on the Au(111) surface with Te as buffer layer. The fabrication of this 2 D layered heterostructure expands 2 D material database, which may bring new physical properties for future applications.
