Optical bandgap of Sb0.2Bi1.8Te3 thin films

摘要

Sb0.2Bi1.8Te3 Thin Films were grown using the thermal evaporation technique on a (001) face of NaCl crystal as a substrate at room temperature. The optical absorption was measured in the wave number range 500 cm−1 to 4000 cm−1. From the optical absorption data the bandgap has been evaluated and studied as a function of the film thickness and deposition temperature. The data indicate absorption through direct interband transition with a bandgap around 0.21 eV. The detailed results are reported.