Effects of cadmium insertion in blue-excited photoluminescence of ZnO

Abstract

The incorporation of small proportions of Cd in ZnO through solid state reaction is proven to be efficient to produce a strong redshift of the blue excited photoluminesce. Due to the diminutive proportion of Cd used, standard X-ray diffractometry is not sensitive to identify the resulting local structural changes, even though proving that long-range order is preserved. Alternatively, they manifest themselves in Raman spectra through the activation of forbidden modes and the strengthening of phonons localization. Through detailed analyzes of photoluminescence data, considering the decomposition of the spectra in emissions of different natures and their modifications as a function of temperature, is shown that the redshift caused by Cd incorporation is a consequence of the strengthening of the contribution of emissions in red-IR range associated to oxygen excess, which is corroborated by quantitative Raman analyses.