One-step room temperature rapid synthesis of Cu2Se nanostructures, phase transformation, and formation of p-Cu2Se/p-Cu3Se2 heterojunctions

Abstract

A tetragonal Cu₂Se film containing a well-aligned nanosheet array with scattered 3D flower-like microstructures on top was synthesized for the first time by a rapid one-step low-energy route, which is beneficial for large scale industrial production due to savings in energy, time and expensive instruments. Phase transformation occurred after scraping the film from the Cu substrate, and heating or grinding the Cu₂Se powder in air. The Cu₂Se/Cu₃Se₂ composite containing p-Cu₂Se/p-Cu₃Se₂ heterojunctions was obtained by simply calcining the Cu₂Se in air at 300 °C for 3 h. The composite has enhanced gas sensing properties towards acetone gas and a lower band gap energy compared to Cu₂Se.