Tailoring the Surface Properties of ZnO Nanowires by ALD Deposition

Year: 2024

Authors: Baratto C., Faglia G.P., Dang TTL., Ferroni M., Holovanova V., Nazarchuk B., Hakola H., Niemi T., Tkachenko N., Golovanov V.

Autors Affiliation: Univ Brescia, CNR INO Unit Brescia, Via Branze 45, I-25123 Brescia, Italy; Univ Brescia, DII, Via Branze 45, I-25123 Brescia, Italy; Hanoi Univ Sci & Technol HUST, Fac Elect Mat & Devices, Sch Mat Sci & Engn SMSE, 1,Dai Co Viet Str, Hanoi 100000, Vietnam; Univ Brescia, DICATAM, Via Branze 45, I-25123 Brescia, Italy; CNR IMM, Via Gobetti 101, I-40129 Bologna, Italy; South Ukrainian Natl Univ, Staroportofrankovskaya Str 26, UA-65020 Odessa, Ukraine; Tampere Univ, Fac Engn & Nat Sci, Korkeakoulunkatu, Tampere 33720, Finland.

Abstract: Innovative research on metal-oxide gas sensors involves nanostructuring and surface modification as key elements to tailor sensitivity and selectivity. This work addresses a ZnO nanowire-based sensing device obtained by coupling a lithographically prepared substrate with hydrothermal ZnO growth, to align and interconnect the nanowires between two electrical contacts. Furthermore, conformal coating by atomic layer deposition technique allows functionalization of the surface of the nanowires with sub-monolayers of Al2O3 and TiO2. A detailed analysis is carried out from a morphological and structural point of view with photoluminescence and Raman spectroscopy and electron microscopy. The material characterization results are analyzed in comparison with the functional characterization in gases toward reducing (NO2) and oxidizing (H2S) gases. Unparalleled sensing enhancement with Atomic Layer Deposition functionalization is obtained for NO2 detection. The passivation role of surface states is discussed combining information from experimental techniques with a proposed model. Nanowires (NWs) growing from selected areas connect each other in the middle of the contact. Conformal coating by atomic layer deposition technique with sub-monolayers of Al2O3 and TiO2 is investigated to modify the surface of the NWs allowing tailoring the selectivity and sensitivity of the nanostructures. image

Journal/Review: ADVANCED MATERIALS TECHNOLOGIES

More Information: The authors of this paper express the sorrow for the untimely loss of Nikolai Tkachenko, a beautiful person and a valuable colleague. V.G. is grateful to the MSCA4Ukraine (No. 1233501), and the Academy of Finland (grant No. 353861) for financial support. This study was also fu nded by the European Union – Next Generation EU M4C2 1.1 within PRIN 2022 -2022JZAA9W.
KeyWords: atomic layer deposition (ALD); chemical sensors; nanowires; ZnO
DOI: 10.1002/admt.202400937