Rutherford backscattering spectrometry characterization of nanoporous chalcogenide thin films grown at oblique angles

GeSbSe chalcogenide thin films deposited by evaporation at different angles ranging from 0 to 85°, either with no substrate rotation or with substrate rotation at constant speed, were characterized by Rutherford backscattering spectrometry (RBS). The analysis allowed the composition and the atomic density of the resulting thin films to be determined. The RBS results show only small variations in composition as a function of the evaporation angle. However, thin film density is greatly reduced for increasing deposition angle, following a trend which agrees well with the optical properties of the films, as well as with predictions from a geometrical growth model. Finally, rotation of the substrate did not significantly affect the composition or the incorporation rate of the resultant film.