In situ AFM and Raman spectroscopy study of the crystallization behavior of Ge2Sb2Te5 films at different temperature

Using in situ atomic force microscope (AFM) and Raman spectroscopy, the real-time crystallization properties of Ge2Sb2Te5 films at different temperature were characterized. The given AFM topograph and phase images revealed that the structure of amorphous Ge2Sb2Te5 films began to change at a temperature of as low as 100 °C. When the temperature reached 130 °C, some crystal fragments had formed at the film surface. Heating up to 160 °C, the size of the visible crystal fragments increased, but decreased at a higher temperature of 200 °C. When the Ge2Sb2Te5 film was cooled down to room temperature (RT) from 200 °C, the crystal fragments divided into crystal grains due to the absence of heating energy. The Raman spectra at different temperature further verified the structure evolution of the Ge2Sb2Te5 film with temperature. This work is of significance for the preparation of Ge2Sb2Te5 films and the erasing of data.