Resonance Raman scattering in In0.45Se0.55 amorphous films

Raman scattering spectra of the In0.45Se0.55 amorphous films recorded in quasi-rectangular geometry with 514, 488 and 458 nm excitation lines of an ion argon laser are presented and discussed. The recorded spectra reveal a density of states character with some contribution of a molecular one. The strongest band at about 125 cm−1 appears to be superposition of two components peaking at about 115 and 127 cm−1, where the former is attributed to the crystal related zone center mode and the latter one to Se8 rings distributed locally. The 115 cm−1 component is the strongest in the RS spectra recorded with a 514 nm laser line, whereas the 127 cm−1 one being the strongest when recorded with 458 nm line. With 488 nm excitation the intensities of the two components are nearly the same. The intensity increase of the 125 cm−1 band is seen to increase with increasing wavelength of the excitation line. The observed intensity variations of the 125 cm−1 band and its two components are interpreted in terms of resonance enhancement due to involvement of two electronic levels of the studied amorphous system with energies equal to 2.4 and 2.7 eV, close to energies of the 514 and 458 nm photons, respectively.