Synthesis via a Microwave-Assisted Wet Chemical Method and Characterization of Bi2Te3 with Various Morphologies

Bi2Te3 with various morphologies, such as microrods, nanoplates, and nanoflowers, has been successfully fabricated by a microwave-assisted method in ethylene glycol solution without any surfactant. The structures and morphologies of the obtained products have been characterized by powder x-ray diffraction and field-emission scanning electron microscopy. Based on time-dependent experiments, a possible formation mechanism of the Bi2Te3 has been proposed. The concentration of KOH in the solution controls the rate of the disproportionation reaction of Te and plays an important role in the formation of the various morphologies of Bi2Te3. The electrical properties of bulk Bi2Te3 materials obtained by cold pressing and then vacuum heat treatment of the Bi2Te3 nanostructures with various morphologies have also been investigated. The highest power factor among the studied samples, ∼17.3 μW cm−1 K−2, was achieved using Bi2Te3 nanoflowers.