Tunable Intense Visible Emission of N-Zno Coatings for Luminescence Applications

Abstract

This research article presents a study on controlling the morphological and optical properties of ZnO nanostructured coatings (n-ZnO) using the vapor phase growth technique assisted by metallic catalysts on silicon substrates. The results demonstrate satisfactory control of the morphological characteristics of the n-ZnO materials, with a mixed 1D-2D matrix obtained by simultaneous competing VLS and VS growth mechanisms. The study also highlights the dependence of the morphology of the structures on the gradient of the Zn gas precursor. Additionally, a suitable defect engineering process by thermal treatments in hydrogen, oxygen, and nitrogen atmospheres is presented to control the visible optical response of the material. This methodology enables the control over multiple recombination centers to modify the optical properties of the n-ZnO. Moreover, the study demonstrates a reversible, controllable, and reproducible process between near-band-edge (NBE) and deep-level emission (DLE). Future perspectives for this research include the use laser ablation treatments for the localized control of the optical and morphological properties of ZnO nanostructures. The present study suggests that this capability can open exciting possibilities for developing advanced nanostructures on modern-day technologies, such as flexible substrates with tailored optical properties and complex morphological features for numerous applications, including optoelectronics, photovoltaics, and sensing.

Keywords: ZnO, Photoluminescence, VLS growth, Nanowires, Optoelectronics