van der Waals epitaxy growth of monolayer copper telluride

Song-Fu Yao^1,3*, Chia-Chun Chen¹, Mario Hofmann², Ya-Ping Hsieh³

¹Department of Chemistry, National Taiwan Normal University, Taipei, Taiwan
²Department of Physics, National Taiwan University, Taipei, Taiwan
³Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan

* Presenter:Song-Fu Yao, email:aurehasd@gmail.com

Few layer two-dimensional copper telluride is expected to be a potential candidate for spintronic, thermoelectric, and solar cells. However, the synthesis of copper telluride remains in bulk, and layer control of Cu_2-xTe is still missing. It was recently found that 2D material grows on 2D material in high uniformity due to its dangling bond-free character. Therefore, we investigate the possibility of growing copper telluride on graphene/copper foil by chemical vapor deposition (CVD). The thickness controlling factor was studied through controlling the precursor concentration on the substrate. To achieve that, we introduce graphite as a diffusion barrier, resulting in a gradient distribution of the precursor concentration on the substrate. Consequently, we observe that copper telluride prefer to grow on the defect-free region of the graphene through van der Waals epitaxial mechanism, which is beneficial to a large area and uniform growth.

Keywords: 2D material, CVD, graphene, epitaxy, copper telluride