Structural and Optical Properties of ZnS:Cu Transparent Nanosheets
Author Affiliations
- 1 Nanoscience Research Laboratory, Department of Physics, Guwahati College, Guwahati-781021, INDIA
- 2 Department of Physics, Diphu Govt. College, Diphu-782462, INDIA
Res. J. Physical Sci., Volume 1, Issue (1), Pages 2-5, February,4 (2013)
Abstract
Semiconductor quantum dots based on luminescent properties of II-VI groups’ elements have attracted special attention to research community due to their fascinating optical and electronic properties. In this work the colloidal solutions as well as thin films on glass substrates of ZnS and ZnS: Cu in PVA (Poly-Vinyl Alcohol) matrix have been prepared through chemical route. The XRD patterns of the as-prepared sample show a mixed type structures comprising both cubic zinc blende and wurtzite hexagonal phases both for ZnS and ZnS:Cu. The crystallinity is improved on Cu doping with presence of clear broad peak with enhanced intensity. Transmission Electron Microscope (TEM) images exhibit the solid triangular shaped nanostructures for undoped ZnS whereas it shows a multiple transparent nanosheets on copper doping. The surfaces of the assembled triangular solid in fact consist of irregular quantum dots distribution having average size of 5 ~ 8 nm. The UV_VIS spectra of ZnS and ZnS:Cu show a band gap of 4 eV and 3.9eV respectively indicating a significant blue shift from its bulk of band gap energy of 3.7eV. A small red shift of band gap as well as blue luminescence on 1% Cu doping indicates that the dopant atoms exist in an interstitial sites.
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