Modification of Nanocrystalline Porous Cu2-xSe Films during Argon Plasma Treatment

Cu2-xSe films were deposited on Corning glass substrates by radio frequency (RF) magnetron sputtering and annealed at 300 degrees C for 20 min under N-2 gas ambient. The films had a thickness of 850-870 nm and a chemical composition of Cu1.75Se. The initial structure of the films was nanocrystalline with a complex architecture and pores. The investigated films were plasma treated with RF (13.56 MHz) high-density low-pressure inductively coupled argon plasma. The plasma treatment was conducted at average ion energies of 25 and 200 eV for durations of 30, 60, and 90 s. Notably, changes are evident in the surface morphology, and the chemical composition of the films changed from x = 0.25 to x = 0.10 to x = 0.00, respectively, after plasma treatment at average ion energies of 25 and 200 eV, respectively.