Optical Properties and Band Gap of Single- and Few-Layer MoTe₂ Crystals

Abstract

Single- and few-layer crystals of exfoliated MoTe₂ have been characterized spectroscopically by photoluminescence, Raman scattering, and optical absorption measurements. We find that MoTe₂ in the monolayer limit displays strong photoluminescence. On the basis of complementary optical absorption results, we conclude that monolayer MoTe₂ is a direct-gap semiconductor with an optical band gap of 1.10 eV. This new monolayer material extends the spectral range of atomically thin direct-gap materials from the visible to the near-infrared