Micro-Raman Scattering Spectra of Ferroelectric KH₂PO₄Thin Films

Abstract

Micro-Raman scattering spectra of KH 2 PO 4 (KDP) ferroelectric thin films were observed in the frequency region of internal modes of PO 4 molecules. To enhance the low intensity Raman signal, we used the surface enhanced Raman scattering technique. The KDP thin films were grown on Ag-films by a slow evaporation method. Raman spectra were observed with a back scattering configuration focused to about 2 μm in spot size on the sample surface. The spectral shape of the symmetric stretching ν 1 mode is good agreement with that of the bulk crystal. The peak-positions and line-widths of the internal modes show the slight change as a function of the sample thickness.