Cathodoluminescence of Zinc Sulfide Films Grown by Single Source Chemical Vapor Deposition

Abstract

The cathodoluminescent properties of zinc sulfide films prepared via single-source chemical vapor deposition of zinc dimethyldithiocarbamate under a variety of precursor fluxes were examined. X-ray photoelectron spectroscopy and depth profiling of the resultant films found bulk carbon impurities of <1% atomic concentrations. X-ray diffraction indicated that the films have a single (111) orientation. Cathodoluminescence spectroscopy found that the light-emitting properties of the films were strongly dependent on the film deposition conditions, with certain films producing a strong band gap emission on a broad background spectrum, while others produced only defect emissions. Transmission electron microscopy indicated that structural defects in the form of threading defects were responsible for the loss of edge emission while carbon contamination at the grain boundaries led to a broad emission in the visible region. Overall the results suggest that ZnS thin films grown using a low cost and straightforward technique such as single-source chemical vapor deposition may have potential applications in producing light-emitting devices.