Optical band gap of Sn0.2Bi1.8Te3 thin films

[摘要] Sn0.2Bi1.8Te3 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 500–4000 cm-1. From the optical absorption data the band gap was evaluated and studied as a function of film thickness and deposition temperature. The data indicate absorption through direct interband transition with a band gap of around 0.216 eV. The detailed results are reported here.

[学科分类] 材料工程

[关键词] Thin films;band gap;optical absorbance;film thickness;size effect.