Ohmic Electrodes Research Articles

Nb2O5/SnO2 Heterojunctions Designed as Optical Absorbers and Microwave Band Filters

Herein, a 200 nm thick films of SnO2 are deposited onto Nb2O5 thin substrates (100 nm) to construct an isotype Nb2O5/SnO2 (NSO) heterojunction devices. The device is constructed using a thermal coating method in a vacuum media of low pressure reaching 10−5 mbar. NSO heterojunctions represent two amorphous/amorphous‐stacked layers that exhibit enhanced light absorption exceeding 170% and 120% in the visible and infrared regions of light spectrum, respectively. In addition, the interface under study displays band conduction offset of 0.60–0.90 eV and valence bad offset of 0.53–0.83 eV, respectively. The NSO device, which is treated as a planner microwaves resonators by contacting it with two Ohmic Pt electrodes, shows AC electrical conduction by the correlated barrier hopping within correlated barriers of average heights of 0.127 eV. Electrical conduction is actualized within scattering time constant of 0.27 ns. NSO microwaves resonators display gigahertz cutoff frequency spectra that suit 6G technology applications. The cutoff limit can be engineered in the range of 1.0–12.0 GHz by altering the driving frequency value. The features of the NSO heterojunctions nominate them for use in optoelectronic, which require high light absorption. The heterojunction devices are also promising for potential use in microwave technology a 6G bands filters.

A 2.8 kV Breakdown Voltage α-Ga2O3 MOSFET with Hybrid Schottky Drain Contact.

Among various polymorphic phases of gallium oxide (Ga2O3), α-phase Ga2O3 has clear advantages such as its heteroepitaxial growth as well as wide bandgap, which is promising for use in power devices. In this work, we demonstrate α-Ga2O3 MOSFETs with hybrid Schottky drain (HSD) contact, comprising both Ohmic and Schottky electrode regions. In comparison with conventional Ohmic drain (OD) contact, a lower on-resistance (Ron) of 2.1 kΩ mm is achieved for variable channel lengths. Physics-based TCAD simulation is performed to validate the turn-on characteristics of the Schottky electrode region and the improved Ron. Electric-field analysis in the off-state is conducted for both the OD and HSD devices. Furthermore, a record breakdown voltage (BV) of 2.8 kV is achieved, which is superior to the 1.7 kV of the compared OD device. Our results show that the proposed HSD contact with a further optimized design can be a promising drain electrode scheme for α-Ga2O3 power MOSFETs.

Room temperature growth of CsPbBr3 single crystal for asymmetric MSM structure photodetector

UV–visible broadband light harvesting ability is critical for photodetectors, and all inorganic perovskite CsPbBr3 is regarded as a promising candidate as the response active material. Herein, a saturated-solution crystallization method is employed to synthesize CsPbBr3 single crystal. Temperature-dependent photoluminescence spectra with one-photon and two-photon excitation are systematically investigated, determining a large exciton binding energy of 39.8 meV. This allows the stable excitonic emission of CsPbBr3 single crystal at room temperature. Subsequently, an asymmetric structure CsPbBr3 photodetector is fabricated by using InGa alloy as the Ohmic electrode and Au as the Schottky electrode. At -8 V, the device exhibits a prominent response to the irradiation from UV to green band with a maximum responsivity of 2.56 A/W, an external quantum efficiency of 580 %, and a detectivity of 1.24 × 1013 Hz1/2 W−1. In addition, the CsPbBr3 photodetector also presents rapid response speeds at both reverse and forward bias voltages and self-powered characteristics owing to the Schottky depletion layer underneath the Au electrode. The demonstration of asymmetric metal-semiconductor-metal (MSM) structure photodetector presents a promising pathway toward next-generation CsPbBr3 optoelectronic devices.

Interface engineering of multilayer cubic boron nitride terminated diamond (111): Rational regulation of Au/diamond Schottky barriers for ambipolar applications

Ultra-wide bandgap semiconductor diamond has become a new hope for developing high power devices owing to excellent properties. We have previously demonstrated that the strong Fermi pinning effect is a critical factor limiting its development. This paper proposes terminal engineering to improve the contact quality between Au and diamond by adjusting the electron affinity of the diamond (111) surface using first-principles calculations. Remarkable changes in interfacial polarity can be achieved by inserting different thicknesses of Cubic Boron Nitride (c-BN) with H/F terminals on the diamond (111) surface. The C-xBNH have the lowest negative electron affinity (−3.80 eV ∼ −2.75 eV), whereas C-xNBF supercells have the highest positive electron affinity (4.52 eV ∼ 8.53 eV). Positive charges accumulate at Diamond/xNB-Au and Diamond/xBNH-Au interfaces, while negative charges build up at the other interlayers. Furthermore, the tunneling probability of the Diamond/xNB-Au interfaces is close to 1, indicating an excellent transmission. The ideal p-type and n-type Schottky barrier heights can be achieved by rational design of the c-BN terminated Diamond contact with Au, and desirable ambipolar regulation can be effectively achieved (Diamond/xNB-Au (x = 2, 3) and Diamond/xNBF-Au (x = 1, 2) for n-type ohmic electrodes and Diamond/xBNF-Au (x = 2, 3) for p-type ohmic electrodes). The proposed strategy allows interface polarity optimization by modifying the surface electron affinity, which can be extended to other high-performance ambipolar diamond devices with the rational design of contact metals.

Precision sub-monolayer manipulation of diamond surface chemistry using laser direct write oxidation in air

Manipulation and patterning of diamond surface chemistry is of interest for a wide range of diamond-based technologies. We report the patterned oxidation of hydrogen-terminated diamond surfaces with sub-monolayer (ML) precision by a deep-UV two-photon process performed in air. Using focused laser pulses of photon energy 4.66 eV (266 nm; below the diamond bandgap of 5.47 eV), hydrogen-terminated (001) surfaces were exposed with calibrated doses to remove carbon with a precision of 0.02 ML. The measurement of the electrical properties of the laser-exposed zone between ohmic electrodes enabled monitoring of the transition from a conducting H-terminated surface to insulating O-terminated. The surface resistance increases by more than 7 orders of magnitude for doses corresponding to 0.5 ML, and the I–V characteristics show a transition from linear to nonlinear for doses above 0.30 ML. We show that this behavior agrees well with a surface percolation model for carrier diffusion in which the laser etch rate for the H-terminated top layer is the same as for O-terminated. Hence, this work reveals an ultra-precise method for modifying the sub-monolayer surface chemistry with the practical advantages of a laser-induced mechanism compared to conventional plasma or chemical processing methods.

Analysis of voltametric data from electrochemical capacitor electrode materials: Method refinement for improved outcomes

A revised model is proposed to improve analysis outcomes from the voltametric analysis of electrochemical capacitor materials and electrodes at different sweep rates (v). Conventional analysis involves breaking down the voltametric current (i) into contributions from capacitive processes (i∝v) and diffusional processes (i∝v1/2). The proposed model introduces a resistance or residual current term, improving the goodness of fit and the quality of data interpretation. This is demonstrated by application of the revised model to artificial voltametric data, electrical double layer capacitor data, as well as pseudo-capacitive electrode data. Analysis with this model also demonstrates the importance of understanding resistive processes in electrode systems, in particular differentiating resistance in the act of charge storage (double layer and redox processes), and ohmic electrode resistance.

Low thermal budget V/Al/Mo/Au ohmic contacts for improved performance of AlGaN/GaN MIS-HEMTs

We report on the highly improved performance of Al2O3/AlGaN/GaN MIS-HEMTs using a V/Al/Mo/Au metal stack as ohmic electrodes. Transfer length method test structures using a V/Al/Mo/Au metal stack annealed at a temperature of 660 °C revealed highly linear current–voltage curves and smooth surface morphology. Compared with reference MIS-HEMTs using Ti/Al/Mo/Au annealed at the standard rapid thermal annealing temperature of 880 °C, V-based devices exhibited less hysteresis of transfer curves and showed higher gate controllability of the drain current, suggesting a highly improved Al2O3/AlGaN interface. Measurements and analyses of capacitance–voltage characteristics of corresponding MIS-capacitors corroborated these findings. The V-based ohmic contact could open new avenues towards enhanced GaN-based MIS-HEMTs performance.

Metal contacts and Schottky barrier heights at boron arsenide interfaces: A first-principles study

The combined feature of high thermal conductivity and high carrier mobility makes cubic boron arsenide (c-BAs) promising for high power and high frequency applications. In BAs-based electronics, the interaction between metals and BAs is crucial, as it significantly affects the electronic properties. One particular parameter is the Schottky barrier height (SBH), which plays a critical role in determining the transmission properties. The interfacial contact effects of BAs (110), (111), and (100) surfaces with a variety of metals have been carefully explored using first-principles calculations in order to characterize their electrical characteristics. For p-type SBHs, over different terminations, there is a strong linear trend with increasing metal work function, with a relatively steeper pinning coefficient of ∼0.2. The results show that the SBHs follow a relation of ϕn(110) > ϕn(111) > ϕn(100). Clear metal induced gap states can be observed at the interfacial BAs, resulting in an enhanced Fermi level pinning effect. The Sc is excellent at generating Schottky contacts with relatively higher SBHs (∼0.9 eV). Pt has the smallest barrier height of ∼0.3 eV, making it ideal for ohmic electrodes with low contact resistance. This work provides insight into the properties at metal–BAs contact interfaces and provides a theoretical basis for the selection of suitable electrodes for high power BAs devices.

Development of Protonic Ceramic Fuel Cell Using BaZr0.2Yb0.8O3-δ as the Electrolyte

Protonic Ceramic Fuel Cells (PCFCs) are attracting attention as next-generation fuel cells that are expected to have lower operating temperatures and higher power generation efficiency than SOFCs. We have reported that BaZr0.8Yb0.2O3-δ does not chemically react with NiO used as a fuel electrode at 1475°C, which is the sintering temperature of the cell, and that the fuel cell can be fabricated by the tape casting method and the fuel electrode and electrolyte co-firing method used in industrial production processes for SOFCs and electronic components. This report describes issues that need to be resolved for the practical application of this cell.Fuel cells were fabricated by laminating green sheets prepared by the tape casting method and co-firing the electrolyte and fuel electrode together. For the air electrode, La0.6Sr0.4Co0.2Fe0.8O3-δ and La0.6Sr0.4CoO3-δ, which are widely used in SOFCs, and newly developed BaZr0.375Yb0.125Co0.5O3-δ were sintered at 900°C to 1000°C. The electrochemical performance of the planar cell was investigated at 600°C under the conditions of a humid fuel gas (i.e., 3% H2O and 97% H2) and humid air (i.e., 3% H2O, 20% O2 and 77% N2). The active area of the planar cell was 0.785 cm2.To evaluate the durability of each cell, continuous power generation tests were conducted at constant current. The durability test was conducted by generating power for 1000 hours at a constant current that resulted in a voltage of 0.85 V at the start of the test, and durability was evaluated by the rate of voltage drop per 1000 hours. As a result, the voltage reduction rate per 1000 hours for the cell using BaZr0.375Yb0.125Co0.5O3-δ as the air electrode was 7.3%/kh. The results clearly show that one of the most significant issues for practical use is the suppression of the rate of voltage drop. The resistance of the cell before and after the durability test were analyzed by electrochemical impedance method, and the ohmic resistance and electrode resistance increased. EPMA analysis of the cell cross section to investigate the cause of degradation revealed diffusion of Ni from the fuel electrode and Co from the air electrode in the electrolyte. Therefore, in order to further improve durability, there is a need to consider adding an anti-diffusion layer to prevent the diffusion of these elements and developing air electrode materials that do not contain Co.

RGB monolithic GaInN-based μLED arrays connected via tunnel junctions

We report a 330 ppi monolithic RGB micro light-emitting diodes (μLED) array of blue, green and red GaInN-based LEDs stacked on the same wafer. Considering it is challenging to form ohmic electrodes on the plasma-etched p-type GaN surface, GaInN-based tunnel junctions were used to connect each LED, and anode electrodes for the blue and green LEDs were formed on n-type AlGaN. The fabricated stacked monolithic μLED arrays were tested at room temperature (approximately 26 °C) and DC. Each μLED emitted blue, green and red with peak wavelengths of 486, 514 and 604 nm at a current density of 50 A cm−2.

Fabrication of Ohmic Contact on N-Type SiC by Laser Annealed Process: A Review

In recent years, because of stringent needs in the fabrication of silicon carbide (SiC) power devices, laser annealing has been introduced to achieve local ohmic contact. In this paper, the laser annealing research for the ohmic contact process of SiC power devices is reviewed, which is mainly divided into four aspects: laser process mechanism, ohmic contact electrode materials, and substrate materials. The effect of laser parameters on ohmic contact and the annealing process on SiC diode devices is also reviewed. Progress of other substrate materials, namely 6H-SiC and semi-insulating 4H-SiC-based devices with laser annealed ohmic contacts, is also briefly discussed, in which formation of semi-insulating SiC ohmic contacts is derived from laser irradiation at the interface to produce 3C-SiC. Some experiment results have been shown in the passage, such as XRD, SEM, TEM, etc. In the review, it points out that the direction of application and development of the laser annealing process for improving the ohmic contact of SiC power devices is highly encouraging.

The improvement of Schottky barrier diodes fabricated only by B ion implantation doping accomplished by refinement of the electrode structure

In this study, we fabricated p-type diamond Schottky barrier diodes (SBD) and performed selective B doping for the p-type channel and Ohmic region by double ion implantation. SBD were redesigned in the configuration and shape of Ohmic and Schottky electrodes to improve device characteristics. The fabricated device exhibited a rectification ratio of approximately 2400 because of decreasing the parasitic resistance to 2.7 × 107 Ω and the ideality factor to 2.7. The Schottky barrier height was obtained to be 1.04 eV. It is indicated that the diamond SBD fabricated only by B ion implantation is improved by refinement of the electrode structure.

Ab-initio study of Schottky barrier heights at metal-diamond (1 1 1) interfaces

Diamond electronic devices have attracted great attention in the field of high power and high frequency applications due to their excellent properties. For diamond electronics, metal and diamond contacts are important for the electronic device performance, with Schottky barrier heights (SBHs) playing a crucial role in the transmission properties of diamond devices. To make sense of their electrical characteristics, the interface supercells of diamond (111) with diverse metals have been explored using first-principles calculations. Clear metal-induced gap states (MIGS) can be observed at the interface, resulting in an enhanced Fermi-level pinning effect, with a pinning factor of 0.3. The results surprisingly show that there is a larger transverse tunneling probability and a smaller longitudinal tunneling probability for all diamond contact interfaces. All interfaces studied are p-type contacts with the metal Fermi level close to the diamond valance band edge. The low work function metals such as Sc and Ti are excellent at generating Schottky contacts with relatively higher SBHs (∼1.0 eV ± 0.6 eV). Pt and Ni have a smallest barrier height of ∼ 0.5 eV, making them ideal for ohmic electrodes with low contact resistance. The calculated SBHs are within the range of the experimental findings. This work gives insight into the electrical structural changes at the contact interface between metal and diamond, which provides a theoretical basis for selecting suitable electrodes for high-power diamond devices.

Investigation of high-temperature performance of WO<sub>3</sub>/<b><i>β</i></b>-Ga<sub>2</sub>O<sub>3</sub> heterojunction deep-ultraviolet photodetectors

Owing to the high bandgap of up to 4.8 eV, Ga<sub>2</sub>O<sub>3</sub> has a natural advantage in the field of deep-ultraviolet (DUV) detection. The Ga<sub>2</sub>O<sub>3</sub>-based photoconductors, Schottky and heterojunction detectors are proposed and show excellent photodetection performance. The Ga<sub>2</sub>O<sub>3</sub> heterojunction detectors are self-driven and feature low power consumption. On the other hand, considering the ultra-wide bandgap and low intrinsic carrier concentration, Ga<sub>2</sub>O<sub>3</sub>-based photodetectors are exhibiting important applications in high-temperature photodetection. In this work, a WO<sub>3</sub>/<i>β</i>-Ga<sub>2</sub>O<sub>3</sub> heterojunction DUV photodetector is constructed and the effect of high temperature on its detection performance is investigated. The <i>β</i>-Ga<sub>2</sub>O<sub>3</sub> films are prepared by metal-organic chemical vapor deposition (MOCVD), and WO<sub>3</sub> films and Ti/Au ohmic electrodes are prepared by spin-coating technology and magnetron sputtering technique, respectively. The current-voltage (<i>I-V</i>) and current-time (<i>I-t</i>) measurements are performed at different ambient temperatures. Parameters including light-dark-current ratio (PDCR), responsivity (<i>R</i>), detectivity (<i>D</i><sup>*</sup>), and external quantum efficiency (EQE) are extracted to evaluate the deep-ultraviolet detection performance and its high-temperature stability. At room temperature (300 K), the PDCR, the <i>R</i>, the <i>D</i><sup>*</sup>, and the EQE of the detector are 3.05×10<sup>6</sup>, 2.7 mA/W, 1.51×10<sup>13</sup> Jones, and 1.32%, respectively. As the temperature increases, the dark current of the device increases and the photocurrent decreases, resulting in the degradation of the photodetection performance. To explore the physical mechanism behind the degradation of the detection performance, the effect of temperature on the carrier generation-combination process is investigated. It is found that the Shockley-Read-Hall (SRH) generation-combination mechanism is enhanced with the increase of temperature. Recombination centers are introduced from the crystal defects and interfacial defects, which originate mainly from the SRH process. Specifically, the dark current comes mainly from the depletion region of WO<sub>3</sub>/<i>β</i>-Ga<sub>2</sub>O<sub>3</sub>, and the carrier generation rate in the depletion region is enhanced with temperature increasing, which leads to the rise of dark current. Similarly, the increase of temperature leads to the improvement of the recombination process, therefore the photocurrent decreases at a higher temperature. This effect can also well explain the variation of response time at a high temperature. Overall, it is exhibited that the WO<sub>3</sub>/<i>β</i>-Ga<sub>2</sub>O<sub>3</sub> heterojunction photodetector can achieve stable self-powered operation even at an ambient temperature of 450 K, indicating that the all-oxide heterojunction detector has potential applications in harsh detection environments.

Fabrication of Low-Threshold Discreet Schottky Barrier Diode Using Natural Pyrite Crystal

A low-threshold schottky barrier diode using natural pyrite has successfully been fabricated for the first time. The schottky and ohmic electrodes were successfully mounted and molded onto natural FeS2(pyrite) crystals. The I-V characteristics of the devices were measured, and the typical Schottky barrier diode characteristics were confirmed. The barrier height estimated by fitting was shown to be as low as 0.60 eV, indicating that the device has low-threshold characteristics.

Corrosion‐Resistive and Low Specific Contact Resistance Ohmic Contacts to Semiconducting Diamonds Using Nanocarbon Electrodes

The realization of diamond‐based advanced devices is interrelated with the fabrication of practical ohmic contacts. Contrary to boron‐doped, the phosphorus‐doped diamonds with interface carbide forming Ti‐based conventional ohmic contacts find their limitation in device fabrication due to the high contact resistance. Herein, nanocarbon ohmic contacts are deposited by a coaxial arc plasma gun on semiconducting diamonds, and their composite structure which facilitates exceptional contact properties is explored. A comparative electrical characterization between nanocarbon ohmic contacts and conventional Ti‐based contacts is performed on a heavily phosphorus‐doped diamond, and they exhibited one‐order declination in specific contact resistance. In addition to the low contact resistance, an ideal ohmic electrode is preferable to have good mechanical adhesion and corrosion resistance for device applications. The contact behavior of n‐type diamond/nanocarbon against an extremely corrosive environment realized by boiling H2SO4 + HNO3 solution is analyzed. The nanocarbon ohmic contacts exhibit excellent corrosion resistance and mechanical adhesion over conventional Ti‐based contacts. A similar trend is also observed for nanocarbon contacts on boron‐doped diamonds. The modest effect on the transfer length of the nanocarbon contacts with respect to acid treatment sessions indicates a tightly bonded diamond/nanocarbon interface and actively suggests their application in highly‐corrosive and harsh environments.

Effects of PCBM loading on high sensitive P3HT based vertical bulk resistive X-ray detector

Recently, semiconductive polymeric materials have attracted attention as an active layer for detecting ionizing radiation because of their excellent properties such as flexibility, easy production, solution processability and low-cost production. This paper presents X-ray detection properties of Poly(3-hexylthiophene) (P3HT):Phenyl C61 butyric acid methyl ester (PCBM) blend structure with different PCBM loading ratios. P3HT:PCBM mixing ratio was changed from 1:0 to 1:2. Top contact of the pure and blend structured device were produced by using a solution based graphite ink. Devices were constructed with vertical bulk resistive architecture within an ohmic electrode structure as ITO/PEDOT:PSS/P3HT:PCBM/Graphite configuration. Graphite electrode was coated on the active layer with the spray coating method. All devices exhibited ohmic current-voltage (I–V) characteristics. The blend structured devices exhibited stable saw-tooth type behaviour in photocurrent responses against the on and off states of X-rays. Saw-tooth type responses could be evaluated as major evidence for a potential usage of organic electronic device technology direct radiation detectors. Although the best sensitivity value to X-ray was obtained with the blend structure with equal ratio, it was observed that the rise and decay times were shortened with the increase in the amount of PCBM in the blend structure from. • P3HT:PCBM active layer based X Ray detectors were fabricated and effect of PCBM ratio was investigated. • Spray coated graphite electrode was used as the top ohmic contact for all devices. • P3HT:PCBM ratio was changed as (1:0), (1:0.5), (1:1), (1:2) and investigate PCBM concentrations how effect X Ray detection parameters with different X Ray dose rates under 10 V bias. • Best sensitivity value to X-ray was obtained with the blend structure with equal ratio of PCBM and P3HT (1:1).

Breakdown Voltage Enhancement of Vertical Diamond Schottky Barrier Diode With Annealing Method and AlO Field Plate Structure

We proposed a simple method to enhance the breakdown voltage (BV) and reduce the turn-on voltage (VON) for diamond vertical Schottky barrier diode (SBD) with Al2O3 field plate (FP) structure. The Al2O3 was deposited by atomic layer deposition at 200 °C. Ti/Pt/Au and Zr/Ni/Au metal stacks were used as ohmic and Schottky electrodes, respectively. Then, this FP terminated SBD was annealed at 400 °C to improve Al2O3 quality and lower Schottky barrier height. The ideality factor and Schottky barrier height are 1.60 and 1.42 eV, respectively. Compared with regular diamond SBD, the BV of annealed diamond SBD was enhanced from 162 V to 386 V with an increasement of 138%, and the VON was decreased from −2.30 to −1.65 V. This method is potential for the development of diamond power devices.

Overcoming the impact of post-annealing on uniformity of diamond (100) Schottky barrier diodes through corrosion-resistant nanocarbon ohmic contacts

Diamond-based Schottky barrier diodes (SBDs) are involved in many technological applications. In a conventional SBD fabrication process that involves interface carbide forming ohmic contacts, a post-annealing step is necessary for ohmic contacts to achieve their operational efficiency. However, this step deteriorates the essential oxygen coverage at the diamond surface which in turn affects SBDs uniformity. So, an additional oxygen termination step is necessary prior to Schottky metal deposition. In this study, a non-conventional fabrication method is introduced using corrosion-resistant nanocarbon ohmic contacts fabricated by coaxial arc plasma deposition. As a result, The SBD parameters including ideality factors and barrier heights exhibited high uniformity with a very small standard deviation for the proposed fabrication process flow when compared with process flow including a post-annealing step. Furthermore, the contact behavior of nanocarbon ohmic electrodes is investigated on a heavily boron-doped diamond film using circular transmission line model theory and a specific contact resistance of ∼10−5 Ωcm2 is obtained, suggesting the practical application of nanocarbon ohmic contacts for diamond-based electronic devices.

Comparative study on the electrochemical performance of Sr(Ti0.3Fe0.7)O3-δ fuel electrode in different fuel gases for solid oxide electrochemical cells

Sr(Ti1-xFex)O3−δ (STF) perovskite has been developed as one of the alternatives to Nickel-base fuel electrodes for solid oxide electrochemical cells (SOCs) that can provide good tolerance to redox cycling and fuel impurities. Recent results on STF fuel electrodes present excellent electrochemical performance and outstand stability both under H2 fuel cell mode and H2O electrolysis mode, however, the electrochemical characteristics in other fuel gases, such as CO, CO–H2 mixture, CH4, and CO–CO2 mixture have not been investigated. Herein, we report the electrochemical performance of Sr(Ti0.3Fe0.7)O3−δ fuel electrode on La0.8Sr0.2MnO3−δ-Zr0.92Y0.16O2−δ (LSM-YSZ) oxygen electrode supported SOCs with thin YSZ electrolyte using different fuel gases. At 800 °C, the peak power density slightly decreased from 0.9 W/cm2 in wet H2 to 0.68 W/cm2 in wet CO under fuel cell mode. However, the cell only showed a peak power density of 0.27 W/cm2 at 800 °C in wet CH4, reaching 0.75 W/cm2 at 850 °C, when the open-circuit voltage increased from 0.9 V to 1.02 V. STF fuel electrode exhibited much worse CO2 electrolysis performance than steam electrolysis, especially in high CO2 concentration due to the increased ohmic resistance and electrode polarization resistance.