Free‐Standing Few‐Layer Tellurene Nanosheets: Simple Solution‐Phase Synthesis and Electronic Structure

Abstract

Mechanical stirring of bulk Te in N-methyl-2-pyrrolidone (NMP) solution at room temperature resulted in the formation of free-standing few-layer (∼1.2–2.8 nm) crystalline ultrathin nanosheets of tellurene with a large lateral thickness (∼1–1.6 μm) as confirmed by atomic force microscopy (AFM). High-resolution transmission electron microscopy (HRTEM) confirms the presence of α- and β-phases of tellurene. First-principle density functional theoretical (DFT) based electronic structure calculations demonstrate the indirect band gap of bi-layer β-tellurene. The band gap decreases with increasing number of layers in the tellurene nanosheet.