Structural and optical properties of CuSe2 nanocrystals formed in thin solid Cu–Se film

• Published in: Infrared physics & technology 2016-05, Vol.76, p.276-284
• Main Authors: Gilić, M., Petrović, M., Kostić, R., Stojanović, D., Barudžija, T., Mitrić, M., Romčević, N., Ralević, U., Trajić, J., Romčević, M., Yahia, I.S.
• Format: Article
• Language: English
• Subjects: Maxwell-Garnett mixing model; Optical properties; Spectroscopy; Thin films
• ISSN: 1350-4495; 1879-0275
• DOI: 10.1016/j.infrared.2016.03.008

[Display omitted] •Two-phase-system, low-pressure modification of CuSe2 and solid solution Cu in Se.•Raman and far-infrared spectra show 10 modes that belong to hexagonal Se and CuSe2.•Continuum medium model of optical phonon confinement in CuSe2 nanocrystal.•Maxwell-Garnett mixing rule was applied. This paper describes the structural and optical properties of Cu–Se thin films. The surface morphology of thin films was investigated by atomic force microscopy (AFM) and scanning electron microscopy (SEM). Formation of Cu–Se thin films is concluded to proceed unevenly, in the form of islands which later grew into agglomerates. The structural characterization of Cu–Se thin film was investigated using X-ray diffraction pattern (XRD). The presence of two-phase system is observed. One is the solid solution of Cu in Se and the other is low-pressure modification of CuSe2. The Raman spectroscopy was used to identify and quantify the individual phases present in the Cu–Se films. Red shift and asymmetry of Raman mode characteristic for CuSe2 enable us to estimate nanocrystal dimension. In the analysis of the far-infrared reflection spectra, numerical model for calculating the reflectivity coefficient of layered system, which includes film with nanocrystalite inclusions (modeled by Maxwell-Garnett approximation) and substrate, has been applied.