Aller au menu Aller au contenu
Physico chemistry of solids, thin films, biotechnologies
Applications for micro & nano- technologies, energy, health ...

> Research > Research-NanoMAT

Publication by José Villafuerte

Published on March 2, 2022
A+Augmenter la taille du texteA-Réduire la taille du texteImprimer le documentEnvoyer cette page par mail cet article Facebook Twitter Linked In
Communique from March 2, 2022 to May 11, 2022

The article entitled "Modulating the growth of chemically deposited ZnO nanowires and the formation of nitrogen- and hydrogen-related defects using the pH adjustment" has been published in Nanoscale Advances.

NanoscaleAdvVillafuerte2022

NanoscaleAdvVillafuerte2022

Here you will find the article by José Villafuerte:
"ZnO nanowires (NWs) grown by chemical bath deposition (CBD) have received a great interest for nanoscale engineering devices, but their formation in aqueous solution containing many impurities needs to be carefully addressed. In particular, the pH of the CBD solution and its effect on the formation mechanisms of ZnO NWs and of nitrogen- and hydrogen-related defects in their center are still unexplored. By adjusting its value in a low- and high-pH region, we show the latent evolution of the morphological and optical properties of ZnO NWs, as well as the modulated incorporation of nitrogen- and hydrogen-related defects in their center using Raman and cathodoluminescence spectroscopy. The increase in the pH is related to the increase in the oxygen chemical potential (µO), for which the formation energy of hydrogen in bond-centered sites (HBC) and VZn-NO-H defect complexes is found to be unchanged, whereas the formation energy of zinc vacancy (VZn) and zinc vacancy-hydrogen (VZn-nH) complexes steadily decreases as shown from density-functional theory calculations. Revealing that these VZn-related defects are energetically favorable to form as µO is increased, ZnO NWs grown in the high-pH region are found to exhibit a higher density of VZn-nH defect complexes than ZnO NWs grown in the low-pH region. Annealing at 450 °C under oxygen atmosphere helps tuning the optical properties of ZnO NWs by reducing the density of HBC and VZn-related defects, while activating the formation of VZn-NO-H defect complexes. These findings show the influence of pH on the nature of Zn(II) species, the electrostatic interactions between these species and ZnO NW surfaces, and the formation energy of the involved defects. They emphasize the crucial role of the pH of the CBD solution and open new possibilities for simultaneously engineering the morphology of ZnO NWs and the formation of nitrogen- and hydrogen-related defects."
A+Augmenter la taille du texteA-Réduire la taille du texteImprimer le documentEnvoyer cette page par mail cet article Facebook Twitter Linked In

Date of update March 2, 2022

Université Grenoble Alpes