Tailoring the optoelectronic and spintronics properties of Cr-doped ZnS nanostructure thin films

This paper discusses the tailoring of the optoelectronic and spintronic of Cr3+-doped ZnS nanostructured electron beam evaporated thin films. The XRD measurements confirm the zinc blende cubic structure for the films with a preferred orientation along the (111) direction. The nanostructured features of the films were verified from the XRD and AFM results. The EDXS and XPS data show the stoichiometric chemical and electronic states of the films. Spectrophotometry measurements for the films show that the energy gap decreases from 3.67 eV to 3.43 eV as the Cr3+ increases from 0 at. % to 8.0 at.%. Such reduction of the Eg of the Cr3+-doped ZnS is attributed to the sp-d coupling. The strong PL asymmetric peak of the Cr3+-doped ZnS is observed, which is quenched and red shifted with increasing Cr doping level. Furthermore, the magnetic measurements show the occurrence of weak room temperature ferromagnetic behavior. On the other hand, the results further show that the magnetization increases with the increase of the Cr3+ dopants up to x = 0.05, then decreases with increasing the Cr doping above x = 0.05. This can be attributed to the development of the antiferromagnetic ordering.