Grain size dependent optical band gap of CdI2 films

[摘要] The thermally evaporated stoichiometric CdI₂ films show good ð‘�?-axis alignment normal to substrate plane for film thickness up to 200 nm. The optical absorption data indicate an allowed direct interband transition across a gap of 3.6 eV in confirmation with earlier band structure calculations. However, part of the absorption data near band edge can be fitted to an indirect band gap of 3 eV. The dependence of band gap on film thickness (> 200 nm) can be explained qualitatively in terms of decreasing grain boundary barrier height with grain size.

[学科分类] 材料工程

[关键词] Optical properties;thin films;halides.