Substrate Heating Research Articles

Low temperature assisted phase transitions in thermally evaporated Cu2Se/Ga3Se2/In3Se2 multilayer thin film structure: Raman signatures of a pristine chalcopyrite CuInxGa1-xSe2 structure

Copper Indium Gallium Selenide (CIGS) thin film solar cell absorber layers are fabricated by the conventional co-evaporation of metal stack precursors followed by a selenization process at a high-temperature range. The article deals with an alternative approach to fabricate the CIGS layer by sequential evaporation of metal selenides followed by a low-temperature treatment (250 °C) during pre-and post-deposition processes. Our post annealing treatment on substrate heat treated film reported a first-ever pristine CuIn0.7Ga0.3Se2 thin film structure without selenization was reported at a very low temperature. A better microstructure with an enhanced grain growth, preferential (112) plane orientation, and Raman signatures of pristine chalcopyrite without a secondary Cu2-xSe phase at the surface was observed. Electron microscopy studies affirm the polycrystalline nature of film structure. Optical analyses have shown near-optimum values as of standard absorber layers. Crucial optical parameters such as refractive index, static and high-frequency dielectric constants were estimated by different relations. The values are concurrent with the semiconductor scale. These features in a low-temperature range optimistically land them as promising candidates in flexible electronics.

Dense, single-phase, hard, and stress-free Ti0.32Al0.63W0.05N films grown by magnetron sputtering with dramatically reduced energy consumption

The quest for lowering energy consumption during thin film growth, as by magnetron sputtering, becomes of particular importance in view of sustainable development goals. A recently proposed solution combining high power impulse and direct current magnetron sputtering (HiPIMS/DCMS) relies on the use of heavy metal-ion irradiation, instead of conventionally employed resistive heating, to provide sufficient adatom mobility, in order to obtain high-quality dense films. The major fraction of process energy is used at the sputtering sources rather than for heating the entire vacuum vessel. The present study aims to investigate the W+ densification effects as a function of increasing Al content in (Ti1-yAly)1-xWxN films covering the entire range up to the practical solubility limits (y ~ 0.67). Layers with high Al content are attractive to industrial applications as the high temperature oxidation resistance increases with increasing Al concentration. The challenge is, however, to avoid precipitation of the hexagonal wurtzite AlN phase, which is softer. We report here that (Ti1-yAly)1-xWxN layers with y = 0.66 and x = 0.05 grown by a combination of W-HiPIMS and TiAl-DCMS with the substrate bias Vs synchronized to the W+-rich fluxes (to provide mobility in the absence of substrate heating) possess single-phase NaCl-structure, as confirmed by XRD and SAED patterns. The evidence provided by XTEM images and the residual oxygen content obtained from ERDA analyses reveals that the alloy films are dense without discernable porosity. The nanoindentation hardness is comparable to that of TiAlN films grown at 400–500 °C, while the residual stresses are very low. We established that the adatom mobility due to the heavy ion W+ irradiation (in place of resistive heating) enables the growth of high-quality coatings at substrate temperatures not exceeding 130 °C provided that the W+ momentum transfer per deposited metal atom is sufficiently high. The benefit of this novel film growth approach is not only the reduction of the process energy consumption by 83%, but also the possibility to coat temperature-sensitive substrates.

Accurate prediction of the critical heat flux for pool boiling on the heater substrate

While the influence of liquid qualities, surface morphology, and operating circumstances on critical heat flux (CHF) in pool boiling has been extensively studied, the effect of the heater substrate has not. Based on the force balance analysis, a theoretical model has been developed to accurately predict the CHF in pool boiling on a heater substrate. An analytical expression for the CHF of a heater substrate is obtained in terms of the surface thermophysical property. It is indicated that the ratio of thermal conductivity (k) to the product of density (ρ) and specific heat (c p) is an essential substrate property that influences the CHF. By modifying the well-known force-balance-based CHF model (Kandlikar model), the thermal characteristics of the substrate are taken into consideration. The bias of predicted CHF values are within 5% compared with the experimental results.

High-quality transparent conductive indium oxide film deposition by reactive pulsed magnetron sputtering: Determining the limits of substrate heating

A transparent conductive oxide (TCO) should have a combination of high electrical conductivity and optical transmission property to fulfill the challenging demands of industrial applications. So far, doped TCOs have been mostly considered to fulfill the technological challenges. In this study, we demonstrate that indium oxide (In2O3) thin films without intentional doping can be deposited with high crystallinity under specific film growth conditions leading to thin films with high mobility, high electrical conductivity, and high transmittance. In2O3 thin films have been deposited by reactive pulsed direct current magnetron sputtering (pulsed DCMS) from an indium target on substrates in a temperature range from room temperature (RT) to 600 °C. Detailed investigations on In2O3 thin films are performed and the film properties such as crystallinity, microstructure, chemical bonding states, electrical and optical properties are revealed. Enhanced plasma density and ionization degree provided by the employed reactive pulsed DCMS and the intentional substrate heating during the thin film deposition give possibility to deposit highly crystalline thin films which are preferentially oriented in (222) direction. The substrate heating enhances the crystallinity of the grown films up to a certain optimum temperature: 400 °C. When the substrate temperature is above 400 °C, the carrier concentration and mobility decrease due to the grain refinement effect caused by growth competition of grains in different orientations. The films grown at 400 °C indicate the presence of high oxygen vacancy concentrations, which can directly be associated with a high charge carrier concentration despite the lack of intentional doping. The undoped In2O3 films in this study grown at 400 °C show highly promising and competitive electrical properties such as low resistivity of 1.28 × 10-4 Ω⋅cm and the high carrier mobility of 69 cm2/Vs. The average transmittance of the In2O3 films with the highest conductivity is found to be greater than 80% in the visible to the near-infrared spectral region owing to an enhancement in the carrier mobility and an optical bandgap in the range from 3.61 eV to 3.77 eV.

Effect of Annealing in ITO Film Prepared at Various Argon-and-Oxygen-Mixture Ratios via Facing-Target Sputtering for Transparent Electrode of Perovskite Solar Cells

Normal perovskite solar cells (PSCs) consist of the following layers: transparent electrode, electron-transport layer (ETL), light-absorbing perovskite layer, hole-transport layer (HTL), and metal electrode. Energy, such as electricity, is produced through light absorbance and electron–hole generation/transport between two electrode types (metal film and transparent conducting film). Among stacked layers in a PSC, the transparent electrode plays the high-performance-power-conversion-efficiency role. Transparent electrodes should have high-visible-range transparency and low resistance. Therefore, in this study, we prepared indium tin oxide (ITO) films on a glass substrate by using facing-target sputtering without substrate heating treatment and investigate the heating-treatment effect on the ITO-film properties for perovskite solar cells (PSCs). Moreover, we fabricated PSCs with ITO films prepared at various oxygen flows during the sputtering process, and their energy-conversion properties are investigated.

Effects of substrate heating on the microstructure and hardness of TiB/Ti6Al4V-ELI during laser in-situ metal deposition

This work investigated the influence of heating temperature (°C) on the microstructure and microhardness of TiB/Ti6Al4V-ELI composite clads that were produced via in-situ alloying using laser metal deposition technique. The samples were produced on a Ti6Al4V base plates which were heated at different temperatures (25°C, 200°C, 300°C, 400°C and 500°C) before they were characterised for microstructure and hardness. It was found that the TiB/Ti6Al4V-ELI sample that was produced on a non-pre-heated base plate was characterized by TiB particles and had the lowest hardness of 511 ± 66 HV. Base plate heating resulted in the formation of TiB whiskers that were dispersed within the titanium matrix. 200°C led to a microstructure with clusters of TiB whiskers hence it had an increased hardness of 651 ± 40 HV. A fine microstructure with homogeneous distribution of the TiB whiskers was obtained at 500°C base plate heating temperature and had hardness of 565 ± 14 HV.

Corrosion behavior of the nickel/nickel interface during the copper‐sacrificial layer release process in micro‐electroforming

AbstractThis study investigates the corrosion behavior of the nickel/nickel (Ni/Ni) interface during the release of the copper‐sacrificial layer in multilayered micro‐electroforming. By altering the pre‐ and posttreatment of multilayered micro‐electroforming (degreasing, in situ anodic treatment, pickling, repassivation, and heat treatment), six different types of Ni/Ni interfaces were obtained. The activities and surface characteristics of the pretreated Ni substrates were investigated via open circuit potential and X‐ray photoelectron spectroscopy. The microstructures of the as‐prepared Ni/Ni interfaces were determined using scanning electron microscopy; after releasing the sacrificial layer in the ferric chloride solution, their corrosion morphologies and corrosion depths were observed under a three‐dimensional microscope with an ultra‐depth of field. The Ni/Ni interface showed a pre‐existing passive layer and interfacial defects. The interface was more prone to attack than the Ni base. Pitting corrosion along the interface boundary occurs via three main processes—initiation, growth, and pit coalescence—with a corresponding reduction in the interfacial adhesion strength and ultimately the structural integrity. The combination of substrate modification (degreasing and pickling) and heat posttreatment effectively avoids localized corrosion. We believe that the surface activation and thermally induced diffusion have worked.

Soft X-ray absorption study of sputtered tin oxide films

The bonding structure of tin oxide (SnOx) films grown by reactive DC magnetron sputtering has been studied by the combination of X-ray diffraction (XRD) and soft X-ray absorption near-edge structure (XANES). The oxygen incorporation in the films has been controlled by the O2 partial pressure (PO2) in the O2/Ar discharge mixture. In addition, the impact of substrate heating and post-deposition flash lamp annealing (FLA) on crystal growth has been studied. In general, it has been stablished a transition from SnO to SnO2 arrangements by increasing PO2, where XRD and XANES provide complementary results about the formation of single- and mixed-phase films. In samples produced at room temperature, XANES gives unique information about such structural evolution, as well as related to defects like the incorporation of O2 molecules at high PO2. FLA on samples grown at room temperature promotes crystal growth and the phase evolution follows the initial structural selectivity. Finally, the optical properties and surface morphology of the films have been correlated with the structural identification.

Laser-based coating process of PEEK powder on stainless steel substrates by using a thulium-doped fiber laser

PEEK is an excellent thermoplastic material for functional coatings due to its outstanding material properties (e.g. biocompatibility, temperature stability, corrosion and wear resistance). In order to reduce the heat input into the base material and to enable a high local selectivity of polymer deposition, a laser-based coating process is a promising approach. In this study, the consolidation of PEEK coatings on stainless steel substrates was investigated experimentally for the first time by using a thulium-doped fiber laser with a wavelength of 1.94 µm. As most polymers exhibit characteristic absorption bands at wavelengths above 1.5 µm, a thulium-doped fiber laser is more appropriate for consolidating thermoplastics in comparison to more common near-infrared laser beam sources with wavelengths of around 1 µm. The effect of admixing fumed silica particles on the flow behavior of the PEEK powder was analyzed by degree of coverage tests to improve the powder deposition process via doctor blade. Furthermore, the influence of an additional substrate heating on the resulting coating characteristics was investigated. Optical microscopy analyses were conducted to characterize the coating surfaces and cross-sections in terms of possible defects. As a result, the flow behavior and hence the deposition process were significantly improved by admixing 1.0 wt. % fumed silica. Optical microscopy analyses verify the basic feasibility of a laser-based coating process with a thulium-doped fiber laser for the consolidation of PEEK powder on stainless steel substrates. In this context, a substrate heating is an important prerequisite to enhance the wetting of the stainless steel substrate and to produce dense as well as adherent PEEK coatings.

Laser-based droplet brazing – Influence of additionally induced thermal energy on joint quality

The demand for semiconductors and microelectronic components is greater than ever and will continuously rise in the future due to increasing automation and digitalization. Also, there is a growing need for robust, high-temperature resistant electrical connections which are essential for the circuit function. Previous investigations have shown that laser-based droplet brazing can create high temperature stable joints e.g. on thin silver layers, without applying an external force on the micro-component to be joined. In order to expand the application field of this process, further combinations of different brazing and substrate materials are investigated. In this paper the influence of additionally induced thermal energy at the diffusion zone was analyzed via shear tests. The studies show, that using brazing alloy CuSn11 in combination with a substrate heating provides the most robust joints on the tested substrate material.

An experimental study on effect of titanium oxide coated heater substrate on pool boiling enhancement

The present experimental study indicates the effect of coating on the enhancement of heat transfer during pool boiling. For this, the aluminium heater substrate of 22 mm * 20 mm was coated with titanium oxide using high velocity oxy fuel (HVOF) method. The coated surface was then used to heat aqueous solutions of acetone, isopropanol, ethanol and distilled water respectively. Simultaneously, heat transfer coefficient (HTC) and excess temperature (dT) were also obtained using aluminium heater substrate without coating. The boiling parameters during coating and non-coating were kept same so that the HTC and dT obtained can be used for comparative study. The heat transfer parametric study was then conducted and the results were presented in graphical form.

Accelerated thermal reaction kinetics by indirect microwave heating of a microwave-transparent substrate.

Macroscopically homogeneous mixtures of p-nitroanisole (pNA) and mesitylene (MES) can be selectively heated using microwave (MW) energy. The pNA solutes agglomerate into distinct phase domains on the attoliter-scale (1 aL = 10-18 L), and these agglomerates can be MW-heated selectively to temperatures that far exceed the boiling point of the surrounding MES solvent. Here, a 1 : 20 mixture of pNA : MES is used as a mixed solvent for aryl Claisen rearrangement of allyl naphthyl ether (ANE). ANE itself does not heat effectively in the MW, but selective MW heating of pNA allows for transfer of thermal energy to ANE to accelerate rearrangement kinetics above what would be expected based on Arrhenius kinetics and the measured bulk solution temperature. This focused study builds on prior work and highlights 1 : 20 pNA : MES as a mixed solvent system to consider for strategically exploiting MW-specific thermal effects.

In situ ellipsometric monitoring of composition and temperature of HgCdTe layers during their growth

An ellipsometric technique has been developed which makes it possible to observe changes in the composition and temperature of cadmium--mercury--tellurium layers during their growing by molecular beam epitaxy. The technique was tested for diagnostics the variations of the composition and the temperature during layer growth in the mode of constant power of the substrate heater and with its sharp change. It was found that the drop in power and a following decrease in the growth temperature were also accompanied by a monotonic decrease in the composition. In the case of a constant heater power, a slight increase in the sample temperature was observed with an almost unchanged composition of the growing layer. Keywords: ellipsometry, mercury--cadmium--telluride, in situ control, epitaxial growth, temperature.

Numerical analysis of bio-digester substrate heating methods

Biogas is a renewable fuel produced by anaerobic digestion of biomass. The performance of anaerobic digestion depends on many factors in which temperature is one of the important parameter. The biogas production rate and yield varies according to the temperature of the substrate. The present work focuses on the importance of temperature in biogas generation from anaerobic digestion and also to compare different in-direct heating methods using ANSYS Fluent K-Epsilon model. The different substrate heating methods are Floor heating, In-vessel heating, and On-vessel heating which can be incorporated into conventional domestic digesters to heat the substrate to the desired optimum temperature for enhanced microbial activity and thereby increased biogas production. Different heating sources are used to heat the slurry like electric coil to heat the circulating fluid and in the case of domestic scale bio digester, solar energy can be utilised. Solar water heater incorporated with a storage system would be appropriate. From the numerical analysis, Floor heating method gave about 5 °C rise in temperature of the slurry and On-vessel showed 5–6 °C rise in temperature and In-vessel showed 6–7 °C rise in temperature of the substrate and was found to be more efficient than other heating methods because it can distribute heat more uniformly to the substrate.

НИЗЬКОТЕМПЕРАТУРНА ІОННО-ПЛАЗМОВА ТЕХНОЛОГІЯ ОСАДЖЕННЯ НАНОСТРУКТУРОВАНИХ ПЛІВОК НІТРИДУ АЛЮМІНІЮ ТА БОРУ

A low-temperature (substrate heating temperature up to 400 °C) ion-plasma technology for the formation of nanostructured AlN and BN films by the method of high-frequency reactive magnetron sputtering of the corresponding targets has been developed (the modernized installation "Cathode-1M"), which has in its technological cycle the means of physical and chemical modification, which allow to purposefully control the phase composition, surface morphology, size and texture of nanocrystalline films. The possibility of using the method of high-frequency magnetron sputtering for deposition of transparent hexagonal BN films in the nanoscale state on quartz and silicon substrates is shown. Atomic force microscopy (AFM) has shown that AlN films can have an amorphous or polycrystalline surface with grain sizes of approximately 20-100 nm, with the height of the nanoparticles varying from 3 to 10 nm and the degree of surface roughness from 1 to 10 nm. It was found that the dielectric penetration of polycrystalline AlN films decreases from 10 to 3.5 at increased frequencies from 25 Hz to 1 MHz, and the peak tangent of the dielectric loss angle reaches 0.2 at 10 kHz. Such features indicate the existence of spontaneous polarization of dipoles in the obtained AlN films. Interest in dielectric properties in AlN / Si structures it is also due to the fact that there are point defects, such as nitrogen vacancies and silicon atoms, which diffuse from the silicon substrate during synthesis and play an important role in the dielectric properties of AlN during the formation of dipoles. The technology makes it possible, in a single technological cycle, to produce multilayer structures modified for specific functional tasks with specified characteristics necessary for the manufacture of modern electronics, optoelectronics and sensorics devices. It should also be noted that the technology of magnetron sputtering (installation "Cathode-1M") is highly productive, energetically efficient and environmentally friendly in comparison with other known technologies for creating semiconductor structures and allows them to be obtained with minimal changes in the technological cycle.

Effect of Zr content on the structure and morphology of CrZrN thin films prepared by reactive DC magnetron co-sputtering method

In this research, nanostructured chromium zirconium nitride (CrZrN) thin film has been deposited on Si(100) substrates by reactive DC magnetron co-sputtering method without in situ substrate heating and post-deposition annealing. The effects of Zr content on thin film structure and morphology were investigated. The Zr content in the films were varied by applied the sputtering current of Zr target (Izr) in the range of 300 to 900 mA, whereas the current of Cr target was kept at 300 mA. The crystal structure, microstructure, morphology, thickness, and chemical composition were characterized by glancing angle X-ray diffraction (GA-XRD), field emission scanning electron microscopy (FE-SEM), and energy-dispersive X-ray spectroscopy (EDS) techniques, respectively. The results showed that the increase of Izr not only increased the deposition rate, but also increased the Zr content of the as-deposited film ranging from 3.9 to 26.5 at%. The as-deposited thin films were formed as a (Cr,Zr)N solid solution, with fcc structure in (111) and (200) plane, where Cr atoms were replaced by Zr atoms in the CrN lattice. The 2θ diffraction peaks were shifted to the lower value as increase of Zr content which was obtained by increased Izr. The nanocrystalline CrZrN structure with crystal sizes smaller than 10 nm structure were calculated for as-deposited thin films. The lattice parameters increased from 4.187 to 4.381 Å, whereas the crystal size decreased from 8.3 to 6.4 nm. The FE-SEM images of all the CrZrN films exhibited compact columnar with dense morphology as a function of Zr content. Moreover, the thickness of the CrZrN thin films was increased of 302 – 421 nm.

Fabrication of Cd-free ZnCuInS/ZnS based inverted quantum dot light-emitting diode: Considering substrate temperature effect on sputtered ZnO layer

Cd-free ZnCuInS/ZnS quantum dot-based light-emitting diodes (QLEDs) were fabricated using metallic sputtered ZnO. The undoped and metallic ZnO film was prepared with substrate heating to enhance the electronics properties of the oxide layer. The semiconductor properties of the ZnO layer were examined by using Hall effect measurements. The structural and morphological properties were observed using x-ray diffraction analysis and field emission scanning electron microscopy. After fabricating the QLED devices, its performances were investigated under DC electrical measurement system and compared with the preparation conditions of the ZnO films. The power efficiency of 11.6 lm/W, current efficiency of 14.1 cd/A, and external quantum efficiency (EQE) of 7.5% were achieved, where the ZnO film was prepared at the substrate temperature of 150 °C, and the Hall mobility of 23.4 cm2/Vs, carrier density of 4.1 × 1020 cm−3 was observed accordingly.

Factors Affecting Substrate Heating with Printed Thermites

AbstractVarious nano‐aluminum thermites were printed and burned on substrates. The reactions were recorded using high‐speed and infra‐red videography in order to investigate the factors affecting the resulting substrate heating. A large number of factors are found to affect the achieved substrate temperature. The thermite's exothermic energy release, gas generation, and burn rate are significant factors, as are the substrate's mass and thermal conductivity. Full‐thickness heating to 360 °C is demonstrated for a standard glass microscope slide. This work will hopefully inspire new applications in actuators or on‐chip thermal processing utilizing the high energy density of printed thermites.

Consolidation of thermoplastic coatings by means of a thulium-doped fiber laser

Thermoplastic polymers such as polyamide 12 (PA12) are of great interest for functional coatings in industry due to their good material properties (e.g., chemical and wear resistance and biocompatibility). In order to provide a high local selectivity of polymer deposition and to shorten the process chain, a laser-based coating process represents a promising approach for generating functional coatings. In this work, a laser-based coating process for PA12 powder on stainless steel substrates is investigated experimentally by using a thulium-doped fiber laser with a wavelength of 1.94 μm. Due to the higher inherent absorption of the laser radiation in the powder material, a thulium-doped fiber laser is more appropriate for processing PA12 powder in comparison to more common near-infrared laser beam sources with wavelengths around 1 μm. The influence of the main process parameters (laser power, scanning speed, hatch distance, and substrate temperature) on the resulting coatings was evaluated. For this purpose, optical microscopic analyses were performed to characterize the coating surfaces and cross sections in terms of possible defects. In order to assess the adhesion between the coating and the substrate, cross-cutting values were determined. On the basis of the quality characteristics regarding the coating surface, a process window was determined to produce a closed melting film, which fully covers the metallic substrate. By an adjustment of the scanning speed (5 mm/s) and line overlap (50%/62.5%), a broadening of the process window could be achieved. An additional substrate heating (T ≥ 90°C) is an appropriate strategy, which enlarges the size of the process window significantly. Optical microscopy analyses and cross-cutting tests verified the suitability of a thulium-doped fiber laser for processing dense PA12 coatings with an adequate adhesion to the stainless steel substrate. The substrate temperature is a decisive process parameter to obtain a homogeneous morphology and to further improve the adhesion between the metallic substrate and PA12 layer.

The Impact of Mn addition on Ta Oxide-Based Electrocatalysts for Oxygen Evolution Reaction in Acid

Hydrogen energy ministerial meeting (H2 EM 2020) was held on Oct. 14, 2020 by the ministry of economy, trade and industry (METI) of Japanese government as online special event with cabinet members and officials from 23 countries, regions, and organizations. In the open session, presenter from industrial company of water electrolysis introduced to improve its technologies for producing hydrogen from renewable energies [1]. In our previous study, the hydrogen producing from renewable energies is called as “Green Hydrogen” [2].Polymer electrolyte water electrolysis (PEWE) has partly commercialized and recently applied its system for the Power-to-Gas (PtG). However, conventional anode is precious metal oxide such as IrO2 and the cost of raw material is expensive. Moreover, it is reported that the IrO₂ is afraid to cause the degradation operating by variable renewable energy (VRE) because the catalytic activity of oxygen evolution reaction became lower by potential cycling of VRE simulation [3]. From this point of view, the non-precious metal oxide anode with high durability against VRE should be required for green hydrogen production. We focused on tatanium oxide-based electrocatalyst (TaOx) and have studied its catalytic activity for oxygen evolution reaction (OER) [4]. In this study, we have investigated the catalytic activity of TaOx with and Mn addition for the OER in acidic solution.Ti rod was used as substarate. TaOx was prepared by RF magnetron sputtering method. In the case of fabrication for Mn-TaOx, Ta metal piece for 60% surface area was set on the Mn disc as additional material. Each partial pressure of Ar and O2 gas was adjusted to 0.23 Pa in fabrication of Mn-TaOx. The substrate heating temperature was constant at 673 K during sputtering. We used conventional three electrode cell with each sample as working electrode while the reversible hydrogen electrode (RHE) and carbon plate were used as reference and counter electrode to demonstrate the electrochemical measurement. In order to evaluate the OER activity of samples, the slow scan voltammetry was performed from 1.2 to 2.5 V vs. RHE in 1 M H2SO4 solution with saturated nitrogen atmosphere at 303 K. We also carried out electrochemical impedance spectroscopy (EIS) to obtain resistance components and semiconducting properties.Figure 1 shows the polarization curve of OER on Ta oxide-based electrocatalysts with Mn addition. The results of Ti oxide-based electrocatalysts with Mo addition (Mo-TiOx) that is our past study [4] is also shown in this figure. The current density was based on geometric surface area. According to figure, the Mn-TaOx has obviously higher OER current than that on Mo-TiOx, and the Tafel slope of OER on Mn-TaOx was 105 mV dec-1 the while the that on the Mo-TiOx was 91 mV dec-1. The peak over 1.5 V was detected from polarization curve of Mn-TaOx in Fig. 1. This peak corresponded to Mn ion, and it suggests that Mn species affected on the OER activity while the amounts of Mn on the sample after electrochemical measurement showed below detection limit from XPS analysis. According to these results, the surface of Mn-TaOx was consisted of Ta oxide mainly with very few amount of Mn after electrochemical measurements. From the results of EIS, resistances of film and charge transfer on Mn-TaOx were lower than that of Mo-TiOx. In addition, the slope of Mott-Schottky plots on the Mn-TaOx was much gentle than that on the Mo-TiOx, and it means that the carrier concentration in Mn-TaOx was higher than that in Mo-TiOx. Therefore, the reason why the Mn-TaOx showed higher OER current than the Mo-TiOx is that both factors of electrical conductivity and catalytic activity were improved.Acknowledgement: This work is partially supported by Toyota Mobility Foundation and ENEOS Tonen General Research / Development Encouragement & Scholarship Foundation.Reference https://www.meti.go.jp/english/press/2020/1015_001.htmlK. Ota, A. Ishihara, K. Matsuzawa, and S. Mitsushima, Electrochemistry, 78, 970 (2010).S. M. Alia, and G. C. Anderson, J. Electrochem. Soc., 166, F282 (2019).K. Matsuzawa, S. Hirayama, K. Sumi, A. Ishihara, Abst. PRiME2020, I01F-2492, Online (2020). Figure 1