摘要
Bulk group IB transition-metal chalcogenides have been widely explored due to their applications in thermoelectrics.However,a layered two-dimensional form of these materials has been rarely reported.Here,we realize semiconducting Cu_(2)Se by direct selenization of Cu(111).Scanning tunneling microcopy measurements combined with first-principles calculations allow us to determine the structural and electronic properties of the obtained structure.X-ray photoelectron spectroscopy data reveal chemical composition of the sample,which is Cu_(2)Se.The observed moire pattern indicates a lattice mismatch between Cu_(2)Se and the underlying Cu(111)-√3×√3 surface.Differential conductivity obtained by scanning tunneling spectroscopy demonstrates that the synthesized Cu_(2)Se exhibits a band gap of 0.78 eV.Furthermore,the calculated density of states and band structure demonstrate that the isolated Cu_(2)Se is a semiconductor with an indirect band gap of-0.8 eV,which agrees quite well with the experimental results.Our study provides a simple pathway varying toward the synthesis of novel layered 2D transition chalcogenides materials.
基金
Project supported by the National Natural Science Foundation of China(Grant Nos.51772087,11904094,51972106,and 11804089)
the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB30000000)
Natural Science Foundation of Hunan Province,China(Grant Nos.2019JJ50034 and 2019JJ50073).
