Structural and photo luminescent properties of uncapped nanocrystalline Cd1−xZnxS solid solutions

Uncapped nanocrystalline Cd1−xZnxS (0.0 ⩽ x ⩾ 0.5) solid solution prepared by microwave assisted combustion route shows hexagonal to cubic phase transformation for even low doping of zinc up to 5 at.% as evident from the X-ray diffraction patterns and the selected area electron diffraction patterns. The solid solutions show a considerable shift in the optical absorption edge from ∼2.43 eV (CdS) to ∼2.73 eV for the equi-atomic composition (Cd0.5Zn0.5S). The blue emission in CdS shows effect of quantum confinement. The photo luminescence spectra of Zn lean compositions (up to 5 at.%) show emergence of a peak at λ ∼ 530 nm along with the blue emission features of CdS. However, solid solutions with higher zinc content (up to 50 at.%), show a systematic increase in the intensity of peak at 530 nm with a blue shift up to 30 at.% of zinc doping. Beyond 30%, a broad blue-green emission with full width at half maxima of ∼100 nm for Cd0.5Zn0.5S is observed.