Vertical nanostructures thin films of CdS and CdTe using low temperatures GLAD

Abstract

This research develops a distinct method for obtaining of thin films of CdS and CdTe with vertical nanostructure morphology grown at low temperatures on the substrate of about 100 °C, were obtained by RF sputtering and sublimation from a vapor effusion source, respectively, both methods were combined with the glancing angle deposition technique. The CdS thin film exhibited a hexagonal structure with preferential plane orientation (002) under compressive stress and a crystallite size of approximately 45 nm. The CdTe film showed a cubic Zinc-Blende structure with an expansive lattice of the unit cell and with preferential plane orientation (111). The size of the crystallites in CdTe was approximately 56 nm. Scanning electron microscopy showed porous nanocolumn structures with vertical nanorods with a width of approximately 16 nm for the CdS and 80 nm for the CdTe, respectively with thicknesses of approximately 335 nm for the CdS and 1330 nm for the CdTe. Using open-source software ImageJ obtained a porosity measurement of approximately 10.4% for CdS and 9.4% for CdTe, respectively. The bandgap energy of the CdS and CdTe thin films was 2.47 eV and 2.51 eV, respectively. The refractive index was 2.5 for CdS and 3.5 for CdTe, respectively. The Urbach energy of the CdS and CdTe was 146 meV and 62 meV respectively. Our results are optimal for possible applications in photovoltaic devices, especially in solar cells and flexible solar cells.