ZnO nucleation into trititanate nanotubes by ALD equipment techniques, a new way to functionalize layered metal oxides

Mabel Moreno,Caterina Salgado,Guillermo González,Luis Velasquez,Eglantina Benavente,Philine Stötzner,Miryam Arredondo,Matthew Mclaren,Quentin M Ramasse,Stefan Förster,Sindy Devis,Paula Solar

doi:10.1038/s41598-021-86722-0

Abstract

In this contribution, we explore the potential of atomic layer deposition (ALD) techniques for developing new semiconductor metal oxide composites. Specifically, we investigate the functionalization of multi-wall trititanate nanotubes, H2Ti3O7 NTs (sample T1) with zinc oxide employing two different ALD approaches: vapor phase metalation (VPM) using diethylzinc (Zn(C2H5)2, DEZ) as a unique ALD precursor, and multiple pulsed vapor phase infiltration (MPI) using DEZ and water as precursors. We obtained two different types of tubular H2Ti3O7 species containing ZnO in their structures. Multi-wall trititanate nanotubes with ZnO intercalated inside the tube wall sheets were the main products from the VPM infiltration (sample T2). On the other hand, MPI (sample T3) principally leads to single-wall nanotubes with a ZnO hierarchical bi-modal functionalization, thin film coating, and surface decorated with ZnO particles. The products were mainly characterized by electron microscopy, energy dispersive X-ray, powder X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. An initial evaluation of the optical characteristics of the products demonstrated that they behaved as semiconductors. The IR study revealed the role of water, endogenous and/or exogenous, in determining the structure and properties of the products. The results confirm that ALD is a versatile tool, promising for developing tailor-made semiconductor materials.

Highlights

In this contribution, we explore the potential of atomic layer deposition (ALD) techniques for developing new semiconductor metal oxide composites
We explore the potential of ALD techniques for the development of new tailor-made semiconductor metal oxide composites based on ZnO and H2Ti3O7 nanotubes
The transmission electron microscopy (TEM) micrograph in Fig. 2a shows that T1 is composed of fiber-shaped particles with very large aspect ratios, while Fig. 2b,c shows some higher magnification transmission electron microscopy (TEM) micrographs typical of the nanotubes used for this study

Summary

Introduction

We explore the potential of atomic layer deposition (ALD) techniques for developing new semiconductor metal oxide composites. Atomic layer deposition (ALD), like other vapour deposition techniques[1], has proven to be a suitable tool for solvent-free fabrication of advanced metal oxide-based functional materials potentially useful to address pressing global problems such as the increase in environmental pollution, the lack of clean energy sources or the development of new healthcare technologies[2,3]. Zinc oxide is a semiconductor, which, beyond having physicochemical environment-friendly properties similar to those of TiO2, possesses interesting photophysical properties such as high exciton binding energy and quite large electron mobility. It has been studied extensively in recent years as an alternative to T iO26,7. Hybrid nanorod (NR) of wurtzite ZnO covered at the tips with amorphous anatase/rutile TiO2 nanoparticles fabricated by hydrothermal treatment (180 °C, 24 h) of previously prepared nanorods and T iO2 nanoparticles, showed photodegradation of methylene blue some five times faster than the best of its components (ZnO NR)[20]

Methods

Results

Conclusion