Ultrafast amorphization in Ge_(10)Sb_(2)Te_(13) thin film induced by single femtosecond laser pulse

摘要

We demonstrate amorphization in a Ge_(10)Sb_(2)Te_(13) (GST) thin film through a nonthermal process by femtosecond electronic excitation. Amorphous recording marks were formed by irradiation with a single femtosecond pulse, and were confirmed to be recrystallized by laser thermal annealing. Scanning electron microscope observations revealed that amorphization occurred below the melting temperature. We performed femtosecond pump-probe measurements to investigate the amorphization dynamics of a GST thin film. We found that the reflectivity dropped abruptly within 500 fs after excitation by a single pulse and that a small change in the reflectivity occurred within 5 ps of this drop.