Effect of Thickness and Annealing on Structural and Optical Properties of Bi2Te3 Thin Films Prepared from Bi2Te3 Nanoparticels

Thin films Bi2Te3 with the thickness range of 37-110 nm have been deposite d on clean glass substrates by the thermally evaporated technique in a vacuum of 1 10 -5 Torr. The influence of thick ness and annealing on the structural and optical properties has been studied. The XRD patterns showed after thermal annealing the Bi2Te3 thin films became polycrystalline in structure. The lattice parameters of the samples were calculated and the structural parameters were discussed on the basis of annealing effect. The AFM images revealed a homogeneous Bi2Te3 dispersion within the layer in higher annealing temperature. Absorption spectra indicate that films were having considerable absorption throughout visible region. Op tical band gap energy decreased with increasing film thickness and annealing temperature.