AACVD Synthesis and Characterization of Iron and Copper Oxides Modified ZnO Structured Films.

Martha Claros,Stella Vallejos,Milena Setka,Yecid P Jimenez

doi:10.3390/nano10030471

Abstract

Non-modified (ZnO) and modified (Fe2O3@ZnO and CuO@ZnO) structured films are deposited via aerosol assisted chemical vapor deposition. The surface modification of ZnO with iron or copper oxides is achieved in a second aerosol assisted chemical vapor deposition step and the characterization of morphology, structure, and surface of these new structured films is discussed. X-ray photoelectron spectrometry and X-ray diffraction corroborate the formation of ZnO, Fe2O3, and CuO and the electron microscopy images show the morphological and crystalline characteristics of these structured films. Static water contact angle measurements for these structured films indicate hydrophobic behavior with the modified structures showing higher contact angles compared to the non-modified films. Overall, results show that the modification of ZnO with iron or copper oxides enhances the hydrophobic behavior of the surface, increasing the contact angle of the water drops at the non-modified ZnO structures from 122° to 135° and 145° for Fe2O3@ZnO and CuO@ZnO, respectively. This is attributed to the different surface properties of the films including the morphology and chemical composition.

Highlights

Zinc oxide (ZnO) is a well-known n-type semiconducting material that possesses a wide band gap (3.37 eV) and large exciton binding energy (60 meV), its relevance in optoelectronics, photonics, and semiconducting devices [1]
The measured static water contact angle for the pure ZnO film was registered as 122◦
The XPS records of the aerosol assisted chemical vapor deposition (AACVD) structures presented an overall shift to lower binding energies, which is usually related to the formation of nonstoichiometric ZnO due to oxygen vacancies induced by the structural size reduction [43]

Summary

Introduction

Zinc oxide (ZnO) is a well-known n-type semiconducting material that possesses a wide band gap (3.37 eV) and large exciton binding energy (60 meV), its relevance in optoelectronics, photonics, and semiconducting devices [1]. The aforementioned usages are strongly dependent on the chemical and physical properties of ZnO. According to the targeted application, transition metals (e.g., Mn, Co, Fe, Cu) and transition metal oxides (e.g., CuxOx, CoxOx, FexOx) have been introduced as second-phase modifier materials in ZnO films to tune its electrical, optical and magnetic properties [4,6,7,8,9]. The modification of ZnO with organic agents such as octadecylphosphonic acid (ODP) or alkanoic acids, as well as inorganic metal oxides such as cuprous oxide (Cu2O), has been explored to improve its wettability [10,11,12,13] and sensing properties [14,15]. There is continuous interest in establishing new synthetic routes that allow tuning the properties of ZnO by the incorporation of second-phase materials

Methods

Results

Discussion

Conclusion