Impact of Temperature on GST/ITO/Soda-Lime Glass Substrate Thin Film Devices

The substrate temperature of Ge₂Sb₂Te₅ (GST) optoelectronic devices can influence various physical parameters, which could be helpful for tuning optoelectronic device structure and working performance as per desired use. Therefore, it is customary to demonstrate the GST/indium tin oxide (ITO)/substrate device structural, optical, and electrical properties with various substrate temperatures, such as room temperature, 150°C, and 200°C. It has been observed that a distinct phase formation in Ge₂Sb₂Te₅ thin films occurs with increasing substrate temperature. An increase in the thickness of the thin films with increasing substrate temperature is verified by field emission scanning electron microscopy (FESEM) cross-sectional view, while the presence of the alloying elements and their particle distributions throughout the configuration are confirmed from energy-dispersive spectroscopy (EDS) and EDS mapping. The developed distinct morphological grains and corresponding roughness parameters of the thin film are interpreted with the help of atomic force microscopy (AFM) results. Moreover, the Raman spectroscopic broad peak of GeSbTe along with a distinguishable difference in GeTe phase peak height is also noticed. The correlation of Raman peak phase formation is described with the help of mapping analysis. Additionally, the Fourier transform infrared (FT-IR) (UV/visible range) transparency property and electrical parameters like I–V and R–V characteristics under the applied distinct voltages are also interpreted for these systems.