Laser-induced periodic surface structures formation and reversible crystallization in amorphous Ge2Sb2Te5 thin films as a result of femtosecond irradiation

Femtosecond laser structuring opens for chalcogenide semiconductor Ge2Sb2Te5 new perspectives in photonics applications due to wide change of its structural and optical properties in such processing. We studied laser-induced modification of amorphous Ge2Sb2Te5 thin films on silicon substrates. The investigations show that periodic relief formation is accompanied by phase transitions to the fcc crystalline phase and back. Furthermore, the irradiated Ge2Sb2Te5 samples demonstrate optical transparency in the near infrared region. The examined structures are interesting for further studies as a base of new memory devices which may possess optical anisotropy and be integrated into fiber optics applications.