Effect of Structural Change on Thermoelectric Properties of the Chalcogenide Ge_2Sb_2Te_5 Thin Films

摘要

Ge_2Sb_2Te_5 (GST) films grown onto SiO_2 (250 nm)/Si substrate at room temperature were annealed at various temperatures to investigate the structural variations. The GST films changed from amorphous to face-centered cubic (FCC) and hexagonal closed packed (HCP) crystalline phases as the annealing temperature increases and the samples annealed at 380°C showed co-existence of the FCC and the HCP. Samples annealed at 380°C showed the highest charge carrier concentration, the lowest resistivity, and the highest power factor.