Temperature dependence of FT-IR absorption and Raman scattering of copper phthalocyanine thin layers deposited on silicon substrate

Abstract

The temperature study of FT-IR absorption and Raman scattering spectra of vacuum deposited CuPc thin layers are presented. Thin films have been prepared by thermal deposition of CuPc layer onto (001) Si substrate. The FT-IR absorption and Raman scattering studies have been performed in the temperature range 77–523 K and 298–513 K, respectively. The Raman spectra were obtained at room temperature in quasi back-scattering geometry. The orientation of molecules in the layers were determined by the method described in our previous paper using polarization analysis of the Raman spectra [14]. The obtained results from Raman experiment are compared with FT-IR absorption spectra of CuPc molecules in KBr pellets and thin layers of CuPc on (001) Si substrate. The change of the intensity, band position and full width at half maximum (FWHM) of Raman and FT-IR modes versus temperature during heating and cooling procedure have been investigated. It has been revealed the fast decrease of the frequency and the intensity of these modes during increase the temperature above 300 K. Some anomalies in temperature dependencies of integrated intensity and FWHM for modes observed in FT-IR absorption and Raman scattering spectra have been observed at 270 K (in FT-IR) and 480 K (in Raman and FT-IR) indicating the change of the structural form.