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- Influence of Nanostructuration on the Vibrational, Electronic and Optical Properties of CrSi2 Thin Films doi link

Auteur(s): Moll Adrien, Hermet P., Bantignies J.-L., Candolfi Christophe, Lenoir Bertrand, Maurin D., Ramonda Michel, Oliviero Erwan, Fréty Nicole

(Article) Publié: The Journal Of Physical Chemistry C, vol. 124 p.28267-28276 (2020)
Texte intégral en Openaccess : openaccess


Ref HAL: hal-03373384_v1
DOI: 10.1021/acs.jpcc.0c08740
Exporter : BibTex | endNote
Résumé:

We report a detailed experimental investigation of the influence of the formation of nano-crystallites on the vibrational, electronic and optical properties of CrSi2 thin films. Both amorphous and nanostructured thin films were investigated by means of electrical resistivity, Hall effect measurements as well as Raman and infrared spectroscopies. We show that both types of films exhibit a semiconducting-like behavior, with the notable difference that the high defect concentrations in amorphous films act as hole donors, modifying the electronic band structure and optical constants. The effect of the film thickness on electrical properties is well captured by the Fuchs-Sondheimer model indicating a decrease in the charge carrier mean free path, likely due to the formation of amorphous/nano-crystallite interfaces that contribute to strongly scatter the charge carriers. Raman spectroscopy performed on nano-crystallized thin films evidences the presence of a Raman-active mode at 229 cm-1 and confirms DFT calculations predicting a mode at 248 cm-1, the observation of which had remained elusive so far in polycrystalline CrSi2. Measurements of the refractive index and dielectric constants of amorphous thin films show a very high refractive index in the mid-IR range. Our results illustrate how the controlled growth of nano-crystallites can be used to tailor the electronic, vibrational and optical properties of amorphous thin films.