Absorption dichroism of monolayer 1T′-MoTe ₂ in visible range

Abstract

Among various transition metal dichalcogenides, MoTe2 has drawn attention due to its capability of robust phase engineering between semiconducting (2H) and semi-metallic distorted octahedral (1T') phase. In particular, 1T'-MoTe2 has been predicted to have intriguing physics such as quantum spin Hall insulator, large magnetoresistance, and superconductivity. Recent progress showed weak antilocalization behavior in 1T'-MoTe2 which is the one of representative characteristics in topological insulator. Here, we grow centimeter-scale monolayer 1T'-MoTe2 on SiO2/Si substrate via chemical vapordeposition and demonstrate dichroism in visible range. Ribbon-like 1T'-MoTe2 flakes were initially nucleated randomly on SiO2 substrate and at a later stage merged to form a continuous monolayer film over the entire substrate. Each flake revealed one dimensional Mo–Mo dimerization feature and anisotropic absorption behavior in visible range (400–600 nm). This allowed us to detect the grain boundary due to stark contrast difference among flakes in different orientations.