Fabrication and Characterization of High-k Dielectric Nickel Titanate Thin Films Using a Modified Sol-Gel Method

Abstract

This research produced high-quality, single-phase nickel titanate (NiTiO 3 ) thin films, a high-k material for gate dielectrics, by a modified sol-gel method. The precursor was prepared by reactions of nickel acetate tetrahydrate and titanium isopropoxide in 2-methoxyethanol with a 1:1 ratio of Ni/Ti in the solution. After coating, the films were post-heat treated between 5001 and 9001C. X-ray diffraction indicated that the films deposited at and above 6001C were single-phase nickel titanate. X-ray photoelectron spectra of a typical thin film revealed that the binding energies of Ni 2p 3/2 and Ti 2p 3/2 electrons were 855.2 and 457.7 eV, respectively. Raman spectra showed eight absorptions between 200 and 800 cm À1 . Scanning electron microscope images showed smooth surfaces. Findings showed the dielectric constant of the NiTiO 3 film to be 41.36 by capacitance-voltage analysis. The results show that single-phase NiTiO 3 film can be prepared by the sol-gel spin coating method and then heat-treated at 6001C.

Photocatalytic Performance of Titanates with Formula MTiO3 (M= Fe, Ni, and Co) Synthesized by Solvo-Combustion Method

“…As annealing temperature was increased at 500 ºC, the reflexions associated to NiO increase slightly. When the temperature was at 600 ºC, it was observed more clearly the presence of the ilmenite (NiTiO 3 ) phase with a rhombohedric structure according to the database JCPDS 33-0960 8,9,27 . In the diffractograms of the three pure phases, where it can be seen that are isostructural and that the reflexions are shifted lightly, this result is natural for the variation of the radius of the cation Fe, Co, and Ni (see Figure 3).…”

“…This method provides significant amounts of the required product with uniformed particle dimensions 8,18,19 , on the other hand, the drawback of this method is its low surface area of the obtained solids; usually close at 1 m 2 /g. They also have been synthesized by precursor polymers 5,11 , mechanochemistry 9 , sol-gel 20,21 , and pechini 22 .…”

“…The titanates of transition metals like Fe, Ni, Co-own diverse properties such as electricity, magnetism and semiconductivity [1][2][3][4] . These properties make titanates widely used in industry, for example, such as semiconductor rectifiers, electrodes of a solid oxide fuel cell, metal-air barrier, hydro-carbonate catalyzers, color mixtures for surface coating and gas sensing devices, among other applications [5][6][7][8][9][10] . Moreover, the application of titanates as photocatalysts is attracting considerable attention for the water and air purification.…”

Synthesis and coloring performance of Ni-geikielite (Ni,Mg)TiO3 yellow pigments: Effect of temperature, Ni-doping and synthesis method

“…M 2+ Ti IV O 3 titanates with ilmenite structure (M = Mg 2+ or transition divalent metals such as Co, Fe, Mn, Ni, Cu and Zn) have been profusely investigated as functional materials showing a wide variety of electrical, magnetic, optical, gas-sensing and even catalytic properties [22][23][24][25][26][27][28][29][30][31][32][33]. For instance, Ni titanates (NiTiO 3 ) have been used for many advanced applications, such as high-k dielectrics, antiferromagnetic or multiferroic materials, photocatalysts for organic dyes, solid lubricants, and so on [25,[30][31][32][33][34][35][36][37].…”

Nitrobenzene hydrogenation over Ni/TiO2 catalyst in vapour phase at atmospheric pressure: influence of preparation method

“…Furthermore, the pH of the solution during the synthesis was maintained at 10. pH also influences the transformation of zirconia phase [24]. [27,28]. Moreover, no peaks corresponding to Ni species were observed and one cannot rule out the formation of Ni species with smaller crystallite sizes (\4 nm), which is the detection limit of XRD technique.…”