Electrical and magnetic properties of atomic layer deposited cobalt oxide and zirconium oxide nanolaminates

Abstract

Introduction Nanostructured Co3O4 in thin film form may possess and demonstrate a variety of properties making the material attractive for several applications. Co3O4 has been investigated as an important electrode material [1-4], gas sensor [5, 6], catalyst [7, 8], or superhydrophobic coating [9]. Co3O4 films have demonstrated resistive switching properties potentially enabling their application in resistive random access memory devices [10, 11]. Cobalt oxide, Co3O4, containing Co 2+ and Co 3+ ions, is recognized as magnetic semiconductor material [12]. Antiferromagnetic behavior with characteristic magnetization-field curves can be demonstrated by Co3O4 nanoparticles [13]. Regarding the possible applications in spintronics, it may occur necessary to activate ferromagnetic coupling in Co3O4 nanoparticles by hybridization with foreign materials, e.g. graphene oxide [14]. Co3O4 films have been grown by oxidation of electron-beam evaporated Co layers [15], pulsed laser deposition [5, 10] chemical bath deposition [1, 6], chemical solution deposition [8, 11], hydrothermal method [2, 13], solvothermal synthesis [9], spray pyrolysis [16]

Synthesis and Characterization of Cobalt Oxide Nanostructures. a Brief Review

“…The low conducting behavior and the lowest dielectric constant for samples with Zn concentration x=0.05 and 0.5 are attributed to their narrow grain size distribution (Figure 2) [60]. The relative permittivity of Co 3 O 4 nanolaminates grown by atomic layer deposition was found to be 30 at the applied electric field frequency of 1000 Hz [61]. Sayed and Gamal investigated the electrical and dielectric properties of sodium carboxymethyl cellulose (Na-CMC)/polyvinyl alcohol (PVA) composite films doped with Co 3 O 4 at different concentrations.…”

Atomic Layer Deposition of CoxOy Films: Oxidants versus Composition

“…Cobalt oxides (Co x O y ), with two primary oxidation states (Co 2+ and Co 3+ ), have been extensively studied in a wide range in both scientific and technological fields, such as photoelectrochemical water splitting, [1] energy production and storage, sensors, [2] and magnetic detecting technologies. [3] Many wellknown thin film deposition techniques, including physical vapor deposition, [4] chemical vapor deposition, [5] and pulsed laser deposition, [6] are utilized to synthesize CoO x -based films.…”

“…Cobalt oxides (Co x O y ), with two primary oxidation states (Co 2+ and Co 3+ ), have been extensively studied in a wide range in both scientific and technological fields, such as photoelectrochemical water splitting, [ 1 ] energy production and storage, sensors, [ 2 ] and magnetic detecting technologies. [ 3 ] Many well‐known thin film deposition techniques, including physical vapor deposition, [ 4 ] chemical vapor deposition, [ 5 ] and pulsed laser deposition, [ 6 ] are utilized to synthesize CoO x ‐based films. Recently, the atomic layer deposition (ALD) technique has been increasingly applied in the design and synthesis of novel film systems due to it offers high reproducibility and precise control over their composition, thickness, and microstructure, making it great potential for the deposition of high‐quality Co x O y films.…”

Properties of Atomic Layer Deposited Nanolaminates of Zirconium and Cobalt Oxides

“…ZrO 2 has been used in nanolaminates as one alternating component together with, e.g., Al 2 O 3 , [47][48][49][50] SiO 2 , 51 Ta 2 O 5 , 52,53 HfO 2 , 53,54 Er 2 O 3 , 55 Gd 2 O 3 , 56 and Y 2 O 3 . 57 Studies on nanolaminates or multilayered structures containing Co 3 O 4 as one of the constituents 58,59 as well as ALD-grown nanolaminates containing both Co 3 O 4 and ZrO 2 59 have so far been quite scarce. In the earlier study devoted to ZrO 2 -Co 3 O 4 nanocomposites grown by ALD using the same chemistry based on cobalt acetylacetonate, zirconium tetrachloride and ozone, 59 the deposition process for cobalt oxide was investigated and established, determining suitable evaporation temperature for Co(acac) 3 precursor, as well as by recording linear relationship between growing mass and the amount of deposition cycles.…”

“…57 Studies on nanolaminates or multilayered structures containing Co 3 O 4 as one of the constituents 58,59 as well as ALD-grown nanolaminates containing both Co 3 O 4 and ZrO 2 59 have so far been quite scarce. In the earlier study devoted to ZrO 2 -Co 3 O 4 nanocomposites grown by ALD using the same chemistry based on cobalt acetylacetonate, zirconium tetrachloride and ozone, 59 the deposition process for cobalt oxide was investigated and established, determining suitable evaporation temperature for Co(acac) 3 precursor, as well as by recording linear relationship between growing mass and the amount of deposition cycles. Using the suitable deposition parameters, ALD growth of ZrO 2 /Co 3 O 4 double layers was demonstrated, together with their performance as dielectric and magnetic materials.…”