Enhanced optical contrast of Ag-doped Ge-Sb-Se-Te phase change films

The phase change material (PCM) Ge2Sb2Se4Te1 film doped by Ag (AGSST) was prepared by the pulsed laser deposition (PLD) method. The crystal structure, chemical bonding and film complex refractive index were investigated. The AGSST undergoes a phase transition through annealing. The extinction coefficient of crystalline (CR) AGSST has been significantly lowered for the communication C-band at 1550 nm, with a figure of merit (FOM) of 7.48, surpassing that of undoped GSST. This outcome delivers chalcogenide PCMs that are potentially in the development of programmable nonvolatile photonics.