Investigation of the structural and optical properties of the CdSe/Yb/CdSe interfaces

In the current study, we report the effect of the ytterbium nanosandwiching on the structural, optical and dielectric properties of the CdSe thin film. The Yb nanosandwiched layer thickness is varied in the range of 10-200 nm. The structural analysis which was carried out by the X-ray diffraction technique has shown that while the grain size increases, the strain, the defect density and the stacking faults are all decreases with increasing Yb thickness in the range of 10-100 nm. Further increase in the Yb thickness to 200 nm decreased the grain size and increased the values of the other structural parameters. Optically, the CdSe absorbability increased 2.6 times at 1.41 eV and the energy band gap redshifts with increasing Yb slab thickness reaching a value of 1.29 eV for a slab thickness of 200 nm. On the other hand, the dielectric spectra displayed two peaks at 2.11 and 1.60 eV for the double layer CdSe films. These two peaks which were assigned to the exciton and electronic transitions, respectively, are observed to redshifts with increasing Yb slab thickness.