Multi-component oxide nanosystems by Chemical Vapor Deposition and related routes: challenges and perspectives

Abstract

Multi-component oxide-based nanosystems are of primary technological importance for various applications of current interest, spanning from optoelectronics to catalysis, from chemical sensing to energy conversion and storage. Such a broad range of functional utilizations results from the joint features of nano-organized systems and the synergistic combination of constituent properties, which, in turn, can be tailored by means of flexible and scalable preparative strategies. An amenable synthetic option potentially meeting these standards is Chemical Vapor Deposition (CVD), either as such or in combination with other fabrication routes. To this regard, the present highlight provides an overview on the CVD-based growth and applicative potential of oxide-based nanocomposite systems. Special attention is devoted to three different categories, i.e. metal/oxide, oxide/oxide and carbon/oxide nanomaterials. For each of them, selected results on synthesis/applications of composite architectures with tailored morphology are presented, trying to address actual challenges and future trends in the field

Solution based CVD of main group materials

“…As far back as 20 years ago commercially available 'simple' b-diketonates, such as [Ga(acac) 3 ], have been used to grow films of Ga 2 O 3 with limited success and high carbon contamination was observed in the resulting films. [156][157][158] Accessible through facile synthetic routes, 159 Recently, the use of these precursors for the deposition of spinel materials via AACVD has been reported.…”

“…The most common method to thin films is CVD, which can be used to deposit on small scale coatings, such as microelectronics and larger areas of growth, for example glass/steel coatings. [3][4][5] The formation of thin films via AACVD is the result of homogeneous or heterogeneous reaction or a combination of both homogeneous nucleation in the gas phase and heterogeneous growth on the substrates. However, both the composition and structure of the deposited materials can be significantly effected by the nature and purity of the precursors.…”

“…Thin films of CuInS 2 , CuInS 2 , CuInSe 2 and CuGaSe 2 have also been grown via AACVD using the precursors [M(E 2 CNMe n Hex) 3 ] (E = S, Se; M = Ga, In) and [Cu(E 2 CNMe n Hex)3 ] 86. UV-vis measurements of the b-In 2 S 3 films showed band gap energies of 2.2 eV.…”

Plasma‐Assisted Fabrication of Fe2O3Co3O4 Nanomaterials as Anodes for Photoelectrochemical Water Splitting

“…Subsequently, functionalization with Co 3 O 4 was carried out by radio frequency (RF)‐sputtering of cobalt on the obtained systems. The key distinctive features of such approaches, that represent highly controllable and versatile tools for the fabrication of supported nanosystems, have already been successfully exploited for the preparation of a variety of oxide nanocomposites, including Co 3 O 4 ZnO and Fe 2 O 3 CuO . The trait d'union of both PE‐CVD and RF‐sputtering is the use of non‐equilibrium plasmas yielding unique activation mechanisms under mild conditions, along with the potential to extend depositions over large areas for a variety of eventual end‐uses .…”

MOCVD of TiO2 thin films from a modified titanium alkoxide precursor

“…In the semiconductor industry, TiO 2 has been studied to replace low‐ k oxide layers for complementary metal oxide semiconductor (CMOS) devices , due its high dielectric constant (80–100 and 20–40 for rutile and anatase, respectively) and low leakage current (10 −5 to 10 −8 A cm −2 at 0.1 MV cm −1 ) . Among the different preparation techniques, metal organic chemical vapor deposition (MOCVD) processes are a preferred choice owing to their inherent flexibility, high growth rates, excellent conformal step coverage, and adaptability to large scale processing . In this regard, several precursors have been employed for the growth of TiO 2 thin films.…”