Nanoscale phase separation in ultrafast pulsed laser deposited arsenic trisulfide (As2S3) films and its effect on plasma etching

We have observed nanoscale phase separation in amorphous arsenic trisulfide (As2S3) films produced by ultrafast pulsed laser deposition and its effect on the surface morphology of the film after plasma etching. When the film was etched in CF4–O2 plasma, a grainy structure was observed on the surface. From Raman and x-ray photoelectron spectroscopies, we concluded that the grainy structure of the etched surfaces comes from the differential chemical attack between different phases in the film.