Changes in Resistance and Bandgap of V2O5 and Ge2Sb2Te5 during Phase Transition

V2O5 and Ge2Sb2Te5 (GST) films have been prepared by magnetron sputtering, and their transformation from amorphous to crystalline state studied by in situ resistance temperature measurements. During the heating process, a two-step transition was observed for both films, revealing three resistances corresponding to amorphous, intermediate, and crystalline states. The two phase-transition temperatures were 371.1°C and 394.0°C for V2O5, much higher than the values of ∼ 172.4°C and 240.4°C for GST. Compared with GST, the resistance of V2O5 was two orders of magnitude higher. The changes in the resistance and bandgap of V2O5 and GST during phase transition were investigated in detail. A phase-change memory device based on V2O5 was fabricated. Compared with GST, V2O5 exhibited a lower operating power and shorter phase-transition time. The application potential of V2O5 and GST for multilevel storage was compared.