Combined method of spectroscopic ellipsometry and photometry as an efficient tool for the optical characterisation of chalcogenide thin films
| Authors | |
|---|---|
| Year of publication | 2009 |
| Type | Article in Periodical |
| Magazine / Source | Journal of Optoelectronics and Advanced Materials |
| MU Faculty or unit | |
| Citation | |
| Field | Solid matter physics and magnetism |
| Keywords | elipsometrie; spektrofotometrie; chalkogenidy; tenké vrstvy |
| Description | The optical characterisation of the As33Se67 and Ge2Sb2Te5 chalcogenide thin films is carried out using the combined method of VASE and SR. This method permits to determine both structural and dispersion parameters describing the thin films exhibiting various defects. The structural model is based on including roughness, overlayers and thickness non-uniformity. The dispersion models are based on parametrisation of the joint density of states. These models, unlike the classical models derived from the Lorentz oscillator model, can describe finite bands which allows to introduce a parameter proportional to the density of electrons. It is shown that this method enables to investigate quantitatively changes in the electronic structure of the materials caused by phase transitions which is demonstrated on the Ge2Sb2Te5. It is shown that the combined method with including true structural and dispersion models is a powerful tool for the optical characterisation of thin films exhibiting disordered structure. |
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