Fast crystallizing GeSb alloys for optical data storage

Abstract

A systematic study is presented on the optical and structural transformations induced in amorphous Ge1−xSbx alloys with Sb contents in the 0.71≤x≤0.91 range by irradiation with 250 ns laser pulses. The results show that only those films richer in Sb than the eutectics (x=0.85) show appreciable optical contrast upon irradiation. The dominant role of Sb in the performances of this family of alloys is analyzed. The transition from a low-reflectivity amorphous phase to a high-reflectivity extended solid solution of Ge in crystalline Sb is shown to be the key for a new generation of fast reversible optical storage materials in which amorphous-crystalline cycling using ultrashort laser pulses is feasible.