Tetranuclear yttrium and gadolinium 2-acetylcyclopentanoate clusters: Synthesis and their use as spin-coating precursors for metal oxide film formation for field-effect transistor fabrication

Lanthanide clusters [Ln(4)(mu(3)-OH)(2)(eta(2)-accp)(4)((mu-O)-eta(2)-accp)(6)](Ln = Y (4), Gd (5); accp = 2-acetylcyclopentanoate) are accessible by treatment of [M(NO3)(3)center dot 6H(2)O] (M = Y (1), Gd (2)) with 3 equiv. of Haccp (3) in presence of NaOH. The molecular structures of 4 and 5 in the solid-state are discussed. The thermal behavior of 4 and 5 was studied by TG under Ar and O-2, showing multistep decomposition processes. Additionally, DSC studies were carried out under an atmosphere of O-2. PXRD measurements of the TG residues confirm the formation of Ln(2)O(3). Spin-coating experiments were carried out with 4 and 5 for Ln(2)O(3) film deposition on silicon substrates. The layers are smooth, close and are of thicknesses of 18.87 +/- 1.13 nm and 25.59 +/- 4.55 nm for Ln = Y and Gd, which was evidenced by SEM and EDX studies. Field-effect transistors were successfully fabricated by deposition of carbon nanotubes on top of the Y2O3 films and formation of palladium contacts by a lift-off procedure. An on/off ratio of more than 4 orders of magnitude is achieved without considerable leakage currents. These results demonstrate the potential use of spin-coated Y2O3 as a gate dielectric in electronic devices. (C) 2018 Chinese Society of Rare Earths. Published by Elsevier B.V. All rights reserved.