Micro-Raman scattering studies of Ge-Sb-Te bulk crystals and nanoparticles

We measured micro-Raman scattering spectra of commercially available Ge-Sb-Te (GST) bulk crystals and GST nanoparticles which were synthesized using a pulsed laser ablation method. The lack of the amorphous Te-Te stretching mode near 150 cm-1 from the Raman spectrum of the bulk sample indicated that the sample was well-crystallized. We also measured GST nanoparticles with different growth conditions, from which we could get information towards the optimal growth conditions for better crystallinity of the GST nanoparticles. Our results suggest that through local structural information, micro-Raman scattering spectroscopy can be used to study the phases and the phase changes in the GST bulk crystals and nanoparticles which is being developed for low-power non-volatile memory applications.