The effect of the Bi source on optical properties of Bi2Te3 nanostructures

► Hexagonal Bi2Te3 nanoplates were achieved by using Bi2O3 as the Bi source. ►Bi2Te3 nanostructures with irregular shape were made by using BiCl3 as the Bi source. ► The effect of the Bi source on optical properties of Bi2Te3 nanostructures was investigated. ► An infrared (IR) active mode shows up in the Raman spectrum of Bi2Te3 hexagonal nanoplates. ► An infrared active mode in the Raman spectrum shows crystal symmetry breaking of nanoplates.