Observation of the femtosecond laser-induced ultrafast amorphization in Ge2Sb2Te5 films by dynamics spectrum

Abstract

We demonstrate ultrafast amorphization in a Ge2Sb2Te5 (GST) film through a nonthermal process by femtosecond pump-probe experiments. A strong absorption peak in 532 nm is founded during the amorphization and the energy level corresponded is about 0.65~3.82 eV by calculations. First-Principles Calculations simulation experiments are used to prove the results of experiment and then explain the mechanism of amorphization of GST. Also, results of experiments show that the time to reach the absorption peak is decided by pulse width and wavelength but not the laser influence.