Detecting ZnS Thin Films on Si Substrates using X-Ray Diffraction

Graduation date: 2014The goal of this research is to determine whether x-ray diffraction (XRD) is a viable method for resolving ZnS thin films on Si substrates. The samples are ZnS thin films of thickness between 50nm and 100nm, on Si substrates that are 0.5mm thick.\ud ZnS and Si have nearly identical lattice parameters and can be interfaced well. They have different absorption spectra, allowing for more efficient solar cells. Research into applications is being done by graduate student Christopher Reidy, as well as methods of ZnS deposition on Si substrates.\ud Nearly identical lattice constants is a good quality for solar cells, which can increase the efficiency considerably. Tunneling electron microscopy (TEM) is a method that directly images the interface, and provides a large amount of information about the interface and quality of a sample. However, it is both costly and time consuming compared to XRD. Research into the process of XRD will determine whether ZnS thin films can be resolved on the Si substrate to produce the same information in a matter of hours rather than days.\ud The scope of this paper includes an introduction to Bragg's law, crystal lattice structure, process descriptions, and conclusions drawn from the results. Ultimately, ZnS Intensity peaks were not observed in the XRD measurements on the Si intensity background