ZnO Films Incorporation Study on Macroporous Silicon Structure.

Lizeth Martínez,Francisco Morales-Morales,Bernardo Campillo,José Campos-Álvarez,Tangirala V K Karthik,Godofredo García-Salgado,Angélica G Hernández,María R Jiménez-Vivanco

doi:10.3390/ma14133697

Abstract

In the present work, we developed hybrid nanostructures based on ZnO films deposited on macroporous silicon substrates using the sol–gel spin coating and ultrasonic spray pyrolysis (USP) techniques. The changes in the growth of ZnO films on macroporous silicon were studied using a UV-visible spectrometer, an X-ray diffractometer (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). XRD analysis revealed the beneficial influence of macroporous silicon on the structural properties of ZnO films. SEM micrographs showed the growth and coverage of ZnO granular and flake-like crystals inside the pores of the substrate. The root mean square roughness (RMS) measured by AFM in the ZnO grown on the macroporous silicon substrate was up to one order of magnitude higher than reference samples. These results prove that the methods used in this work are effective to cover porous and obtain nano-morphologies of ZnO. These morphologies could be useful for making highly sensitive gas sensors.

Highlights

At present, the effort to obtain nanostructures/hybrids from semiconducting materials has attracted considerable interest in the scientific community due to the possible superior functional properties that they could present compared to the individual components assembling composites
Mirela Suchea et al studied zinc oxide (ZnO) transparent films deposited on crystalline silicon (cSi) and glass substrates and found that the gas sensing characteristics of the ZnO films were highly influenced by surface morphology [40]
The ZnO pore decoration of macroporous silicon (mPS) substrates revealed the formation of granular nanocrystals for the sol–gel spin-coating method and flake-like crystals for the ultrasonic spray pyrolysis (USP) method

Summary

Introduction

The effort to obtain nanostructures/hybrids from semiconducting materials has attracted considerable interest in the scientific community due to the possible superior functional properties that they could present compared to the individual components assembling composites. Among the related experimental works, zinc oxide (ZnO) stands out due to its morphological and physical properties. The advantages of using such morphologies derive from the large surface-to-volume ratio, high specific area and surface roughness that they can present [21]. These ZnO morphologies have been used to realize sensors for various gases. These include CO2, NO2, CO, NH3, O3, H2S, C2H5OH and H2 [17,21,22,23,24,25,26,27]

Methods

Results

Conclusion