Growth of ZnO Nanostructures Produced by MOCVD: A Study of the Effect of the Substrate

Abstract

A study of the influence of the substrate mismatch on the growth of ZnO nanostructures is reported. ZnO nanostructures are deposited, by a simple catalyst-free metal-organic (MO)CVD approach, onto various substrates, such as SrTiO 3 (100), Si(100), and Al 2 O 3 (0001), using a novel diamine adduct of zinc bis-2 thenoyl-trifluoroacetonate (Zn(tta) 2 Á tmeda, Htta ¼ CF 3 COCH 2-COC 4 H 3 S, tmeda ¼ N,N,N(,N(-tetramethylethylenediamine). Structural characterizations indicate that both morphology and crystalline structure of the obtained ZnO nanostructured systems strongly depend upon the crystalline mismatch with the substrate. Room-temperature cathodoluminescence (CL) spectroscopy is used to characterize the optical properties of the various nanostructures. The resulting cathodoluminescence spectra of all the samples show the presence of a strong and broad green band around 2.4 eV.

MOCVD of ZnO Films from Bis(Ketoiminato)Zn(II) Precursors: Structure, Morphology and Optical Properties

“…[2,[13][14]25,38] Contributions to this component from carbonate species arising from air exposure were also likely to be present, as confirmed from the surface C1s line shape (not shown), that displayed a minor component located at BE ¼ 288.4 eV. [36,37] As a result, typical surface O/Zn atomic ratios were higher than the expected value for ZnO (1.8-2.0).…”

“…[1][2][3][4][5][6][7][8][9][10][11] There have been several reports on the fabrication of ZnO thin films or nanostructures, including thermal evaporation, sputtering, pulsed laser deposition, molecular beam epitaxy (MBE), sol-gel, atomic layer deposition (ALD), and MOCVD. [1,6,10,[12][13][14] Among them, the latter is by far the most promising technique for large scale production, and more importantly, by varying the CVD process parameters and nature of the precursors, it is possible to regulate the morphology and structure of the films. The precursor chemistry for ZnO-based materials has focused on various compounds, typically Zn II acetate, [15] zinc alkyls (both methyl and ethyl), [4,[16][17][18][19][20][21][22][23] and b-diketonates (mainly Zn (acac) 2 , with acac ¼ 2, 4-pentanedionate).…”

Structural, Optical, and Electrical Characterization of ZnO and Al‐doped ZnO Thin Films Deposited by MOCVD

“…of ZnO films, [16][17][18] using the friendly to use and environmentally safe Zn precursor, Zn(tta) 2 tmeda (Htta ¼ thenoyl-trifluoroacetone, tmeda ¼ N,N,N 0 ,N 0 -tetramethylethylendiamine). In particular, we have implemented a multimetal (Al/Zn) liquid source based on the aforementioned Zn(tta) 2 tmeda and Al(acac) 3 precursors.…”

“…AZO materials have been fabricated in the form of thin films using MOCVD based on the implementation of the already tested Zn(tta) 2 tmeda precursor [16][17][18] mixed with the classic Al(acac) 3 source to form a multimetal, liquid, single source that can be reproducibly evaporated with the required Zn/Al ratio upon changing the molar concentration of the multimetal source. This procedure, analogous to the previously reported molten multimetal source approach, [19] adopts miscible elemental precursors among which a specific source (presently Zn), once melted, acts as a solvent for the remaining precursor, thus forming the desired multimetal source.…”

Deposition of ZnO Nanoparticles on Calcite and Studies on their Optical Properties and Photocatalytic Activity

“…11 Metal organic chemical vapour deposition (MOCVD) has been used for the deposition of ZnO nanoparticles on substrates such as SrTiO 3 (100), Si (100), and Al 2 O 3 (0001). 12 ZnO nanorods have been deposited on silica by physical vapour deposition. 13 ZnO nanorods have been deposited by chemical bath deposition on a glass substrate.…”