Chemical Synthesis and Properties of Novel Bi2Se3 Nanostructures and Microplatelets

Abstract

Bi₂Se₃ nanostructures, microsised fibre bundles, and platelets have been synthesised through a simple chemical spray pyrolysis route on glass substrates. Low substrate temperatures (Tsub) favoured growth of nanostructures while elevated Tsub was accompanied by increased grain growth and formation of microsised platelets. The nanostructures were identified as nanorods, nanofibers, nanotubes, nanoflowers, and nanoneedles of various aspect ratios. There was an observed red shift of the optical band gap (Egopt) with increased Tsub from 2.40 eV at 95°C to 1.25 eV at 360°C. Thermo probe measurements confirmed n-type conductivity with dark resistivities which followed a near exponential decline with elevated Tsub. The observed changes in optoelectronic properties existing in the different Tsub regimes were explained on the basis of microstructural and textural changes in the pristine clusters.