Low-temperature atomic layer deposition of ZnO thin films: Control of crystallinity and orientation

Malm, Jari; Sahramo, Elina; Perälä, Juho; Sajavaara, Timo; Karppinen, Maarit

doi:10.1016/j.tsf.2011.02.024

Cited by 99 publications

(69 citation statements)

References 46 publications

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“…For 1,4-cyclohexanediol the melting and boiling points are 98 and 150 °C, respectively, being lower than those for HQ (172 and 285 °C), Hence it is important to note that crystalline ZnO thin films can be grown in an wide temperature range, and at temperatures considerably lower than the deposition temperature employed for the present ZnO:HQ superlattices. 51 …”

Section: Electronic Properties and Band Structure Engineeringmentioning

confidence: 99%

Atomic-Level Structural and Electronic Properties of Hybrid Inorganic–Organic ZnO:Hydroquinone Superlattices Fabricated by ALD/MLD

2015

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Ab initio calculationsWe investigate crystalline ZnO:hydroquinone (HQ) superlattices grown layer-by-layer by the combined atomic/molecular layer deposition (ALD/MLD) technique; such ALD/MLD layerengineered inorganic-organic thin films form a fundamentally new category of functional coherent hybrid materials that cannot be prepared by any other existing technique. Using quantum chemical methods, we derive atomic-level structural models for the ZnO:HQ superlattices and investigate their structural, spectroscopic, and electronic properties. By comparing the theoretical results with our experimental data we provide a detailed interpretation of experimentally measured infrared spectra, proving the presence of organic interfaces within the crystalline ZnO:HQ superlattices. We moreover show how the band structure of the hybrid material can be tailored by simple and experimentally feasible modifications of the organic constituent. The guidelines for the bandstructure engineering of ZnO:HQ superlattices should be valuable for the systematic enhancement and exploitation of the functional properties of ALD/MLD-grown inorganic-organic superlattices and nanolaminates in general.

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Section: Electronic Properties and Band Structure Engineeringmentioning

confidence: 99%

Atomic-Level Structural and Electronic Properties of Hybrid Inorganic–Organic ZnO:Hydroquinone Superlattices Fabricated by ALD/MLD

2015

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“…15 DEZ has high vapor pressure and reactivity with water, and the process is stable at temperatures even as low as room temperature; thus, ALD can be used to produce good quality ZnO thin films for polymers and other temperature sensitive substrates. 10,19,20 The ALD growth on polymers is strongly dependent on the nature of the polymer and on the ALD precursors. 11,21 For some polymers, reactive sites that can covalently bind the reactants at the initial stages of deposition are not available and the deposition initiates only after a certain number of cycles.…”

Section: Introductionmentioning

confidence: 99%

Nucleation and growth of ZnO on PMMA by low-temperature atomic layer deposition

Napari

Malm

Lehto

et al. 2014

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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ZnO deposition on metal substrates: Relating fabrication, morphology, and wettability J. Appl. Phys. 113, 184905 (2013) ZnO films were grown by atomic layer deposition at 35 C on poly(methyl methacrylate) substrates using diethylzinc and water precursors. The film growth, morphology, and crystallinity were studied using Rutherford backscattering spectrometry, time-of-flight elastic recoil detection analysis, atomic force microscopy, scanning electron microscopy, and x-ray diffraction. The uniform film growth was reached after several hundreds of deposition cycles, preceded by the precursor penetration into the porous bulk and island-type growth. After the full surface coverage, the ZnO films were stoichiometric, and consisted of large grains (diameter 30 nm) with a film surface roughness up to 6 nm (RMS). The introduction of Al 2 O 3 seed layer enhanced the initial ZnO growth substantially and changed the surface morphology as well as the crystallinity of the deposited ZnO films. Furthermore, the water contact angles of the ZnO films were measured, and upon ultraviolet illumination, the ZnO films on all the substrates became hydrophilic, independent of the film crystallinity.

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“…ZnO is of great interest thanks to the co-presence of both semiconducting and PE properties, together with the possibility of being easily synthesized in a lot of different micro/nano structures, like porous [38] and compact [39] thin films, micro/nanowires [40,41], nanorods [42], or nanobelts [43]. Among all of the aforementioned structures, the thin film one is of particular interest since many deposition techniques, like magnetron sputtering [44], pulsed-laser deposition [45], sol-gel [46], chemical vapor deposition [47], and atomic layer deposition [48] can be exploited for growing high-quality ZnO layers. Thin-film technologies have the main advantage of being fully compatible with semiconductor processing, and allow the deposition of ZnO on large-area substrates through repeatable and controllable processes, fully extendable to large-scale industrial production.…”

Section: Introductionmentioning

confidence: 99%

Development of a Flexible Lead-Free Piezoelectric Transducer for Health Monitoring in the Space Environment

et al. 2015

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Abstract:In this work we report on the fabrication process for the development of a flexible piezopolymeric transducer for health monitoring applications, based on lead-free, piezoelectric zinc oxide (ZnO) thin films. All the selected materials are compatible with the space environment and were deposited by the RF magnetron sputtering technique at room temperature, in view of preserving the total flexibility of the structures, which is an important requirement to guarantee coupling with cylindrical fuel tanks whose integrity we want to monitor. The overall transducer architecture was made of a c-axis-oriented ZnO thin film coupled to a pair of flexible Polyimide foils coated with gold (Au) electrodes. The fabrication process started with the deposition of the bottom electrode on Polyimide foils. The ZnO thin film and the top electrode were then deposited onto the Au/Polyimide substrates. Both the electrodes and ZnO layer were properly patterned by wet-chemical etching and optical lithography. The assembly of the final structure was then obtained by gluing the upper and lower Polyimide foils with an epoxy resin capable of guaranteeing low outgassing levels, as well as adequate thermal and electrical insulation of the transducers. The piezoelectric behavior of the prototypes was confirmed and evaluated by measuring the mechanical displacement induced from the application of an external voltage.

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Low-temperature atomic layer deposition of ZnO thin films: Control of crystallinity and orientation

Cited by 99 publications

References 46 publications

Atomic-Level Structural and Electronic Properties of Hybrid Inorganic–Organic ZnO:Hydroquinone Superlattices Fabricated by ALD/MLD

Atomic-Level Structural and Electronic Properties of Hybrid Inorganic–Organic ZnO:Hydroquinone Superlattices Fabricated by ALD/MLD

Nucleation and growth of ZnO on PMMA by low-temperature atomic layer deposition

Development of a Flexible Lead-Free Piezoelectric Transducer for Health Monitoring in the Space Environment

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