Formation of Pb-Sn Janus particles on the surface of lead-tin telluride films during ion-plasma sputtering

The formation of Janus-like particles of Pb-Sn during ion-plasma treatment of the surface of lead-tin telluride films was found. Pb_0.6Sn_0.4Te films 2 μm thick were grown on (111) BaF₂ substrates by molecular beam epitaxy. The ion-plasma treatment of the samples was carried out in a high-density low-pressure radio frequency inductively coupled plasma at an ion energy of 75 eV and 25 eV. The duration of the sputtering process was 240 s. The evolution of the film surface morphology and the formation of Pb-Sn Janus particles with nano- and submicron sizes have been studied.