We report on the collective integration technology of vertically aligned nanowires (NWs). Si and ZnO NWs have been used in order to develop a generic technological process. Both mineral and organic planarizations of the as-grown nanowires have been achieved. Chemical vapour deposition (CVD) oxides, spin on glass (SOG), and polymer have been investigated as filling materials. Polishing and/or etching of the composite structures have been set up so as to obtain a suitable morphology for the top and bottom electrical contacts. Electrical and optical characterizations of the integrated NWs have been performed. Contacts ohmicity has been demonstrated and specific contact resistances have been reported. The photoconducting properties of polymer-integrated ZnO NWs have also been investigated in the UV-visible range through collective electrical contacts. A small increase of the resistivity in the ZnO NWs under sub-bandgap illumination has been observed and discussed. A comparison of the photoluminescence (PL) spectra at 300 K of the as-grown and SOG-integrated ZnO nanowires has shown no significant impact of the integration process on the crystal quality of the NWs.
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http://dx.doi.org/10.1088/0957-4484/19/34/345304 | DOI Listing |
ACS Omega
December 2024
Semiconductor Physics Group, University Ulm, 89081 Ulm, Germany.
In this work, the sensing ability and the underlying reaction pathways of HS adsorption on two nanomaterial systems, pristine zinc oxide (ZnO) nanowires (NWs) and gold functionalized zinc oxide nanowires (Au@ZnO NWs), were explored in a side-by-side comparison of optical and electrical gas sensing. The properties of optical sensing were analyzed by photoluminescence intensity-over-time measurements (-) of as-grown ZnO NW samples, and the electrical gas-sensing properties were analyzed by current-over-time measurements (-) of ZnO NW chemically sensitive field-effect transistor (ChemFET) structures with a gas-sensitive open gate. The ZnO NWs were grown by high-temperature chemical vapor deposition (CVD) and thereafter surface-functionalized with a thin Au nanoparticle layer by magnetron sputtering.
View Article and Find Full Text PDFSensors (Basel)
October 2024
SENSOR Laboratory, University of Brescia, Via D. Valotti 9, 25133 Brescia, Italy.
We are proposing a novel self-assembled monolayer (SAM) functionalized ZnO nanowires (NWs)-based conductometric sensor for the selective detection of hydrogen (H). The modulation of the surface electron density of ZnO NWs due to the presence of negatively charged terminal amine groups (-NH) of monolayers leads to an enhanced electron donation from H to ZnO NWs. This, in turn, increases the relative change in the conductance (response) of functionalized ZnO NWs as compared to bare ones.
View Article and Find Full Text PDFMicromachines (Basel)
September 2024
Institute of Semiconductor Technology, Technische Universität Braunschweig, 38106 Braunschweig, Germany.
The search for a synthesis method to create longer ZnO NWAs with high-quality vertical alignment, and the investigation of their electrical properties, have become increasingly important. In this study, a hydrothermal method for growing vertically aligned arrays of ZnO nanowires (NWs) using localized heating was utilized. To produce longer NWs, the temperature environment of the growth system was optimized with a novel reaction container that provided improved thermal insulation.
View Article and Find Full Text PDFACS Appl Mater Interfaces
November 2024
Bendable Electronics and Sustainable Technologies (BEST) Group, Department of Electrical and Computer Engineering, Northeastern University, Boston, Massachusetts 02115, United States.
Large area electronics (LAE) with the capability to sense and retain information are crucial for advances in applications such as wearables, digital healthcare, and robotics. The big data generated by these sensor-laden systems need to be scaled down or processed locally. In this regard, brain-inspired computing and in-memory computing have attracted considerable interest.
View Article and Find Full Text PDFNanoscale
November 2024
Instituto Interdisciplinario de Ciencias Básicas (ICB-CONICET), Universidad Nacional de Cuyo, Mendoza 5502, Argentina.
Zinc oxide nanowires (ZnO NWs) possess a unique one-dimensional (1D) morphology that offers a direct pathway for charge transport. In this article, we present the first application of the real-time time-dependent density functional tight-binding (real-time TD-DFTB) method for a model hybrid system consisting of a catechol molecule adsorbed on a ZnO nanowire. The rationalization of the photoinduced electron injection to the 1D nanostructure is attained through quantum dynamics simulations, stressing the role of charge transfer in the new optical transitions upon dye adsorption.
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