Low Work Function Research Articles

A novel dual functional gradient Zn(O,S)/Mg electron-selective contact for dopant‐free silicon solar cells with efficiencies approaching 21 %

Dopant-free carrier-selective contacts have the potential to mitigate or eliminate parasitic absorption, auger recombination losses, etc. Therefore, the vigorous development of dopant-free carrier-selective contact materials is an important way to enhance the performance of crystalline silicon (c-Si) photovoltaics. This study presents the concept of magnetron sputtering gradient deposited zinc oxide (Gd-Zn(O,S)) combined with a low work function magnesium metal layer. Subsequently, the Gd-Zn(O,S)/Mg bifunctional layer was further investigated and optimised to determine its suitability as a contact layer for electron transfer in c-Si solar cells. This strategy simultaneously enables a good passivation and a low contact resistance. The c-Si(n)/a-Si:H(i)/Gd-Zn(O,S)/Mg devices are constructed and achieved an optimal contact recombination current density (J0) of approximately 1.51 fA cm−2, along with a minimum ρc of approximately 35.89 mΩ.cm2. As a consequence, the power conversion efficiency of a prototype silicon heterojunction solar cell is 20.92 %. This study demonstrates that the strategy of replacing the a-Si:H(n) electron transport layer with Gd-Zn(O,S) is an effective approach for improving the SHJ cell. This study also provides new perspectives for designing novel dopant-free carrier-selective contact structures.

A new attempt to further reduce the work function of the cesiated surface: The strongest electronegative element fluorine co-adsorption with cesium on Mo (001) surface

The efficiency of hydrogen negative ion production in negative ion sources depends on the work function of the molybdenum surface. Deposition of cesium (Cs) atoms on the Mo surface reduces the work function from over 4.0 eV to about 1.50–1.80 eV. However, the Fermi level remains below the affinity level (−0.75 eV) of hydrogen negative ions. To explore further reduction methods, the work function of Cs co-adsorbed with fluorine on the Mo (001) surface was studied using DFT calculations. The results show that at 4/16 θ Cs coverage, adding fluorine can reduce the work function, achieving the lowest value of 1.40 eV at 8/16 θ F coverage. Analysis reveals a significant vacuum-inward dipole moment with fluorine-Cs co-adsorption, favorably reducing the work function. However, fluorine’s strong electronegativity also creates a surface-directed dipole moment, increasing the work function. Introducing fluorine is beneficial only at 4/16 θ Cs coverage, indicating that precise control of Cs coverage is necessary to achieve lower work functions.

Atom layer deposited TiO2 electron transport layer for silicon heterojunction solar cells to achieve high performance

Silicon/compound heterojunction (SCH) solar cells based on p-type and n-type c-Si wafers using atom layer deposition-TiO2 and low work function metal as the electron transport layer and rear electrode are fabricated. Efficiencies of 20.6 % and 21.6 % are achieved on p-type and n-type silicon solar cells, respectively. High Voc exceeding 700 mV have been realized on both kinds of Si wafers. Special attention has been paid to the SCH solar cells based on p-type c-Si wafers in which the TiO2 electron transport layer serves as the emitter. Carrier transport mechanisms and junction characteristics of the SCH solar cells are analyzed based on dark J-V measurement. The formation of a strong inversion layer at the Si surface region is determined, which implies the high Voc potential of the SCH solar cells based on p-type Si. An optical loss analysis is performed along with a possible solution to further improve the Jsc. The feasibility of TiO2 applied as an efficient electron transport layer (emitter) in p-type SCH solar cells with high performance has been showed.

Inkjet‐Printed Flexible and Transparent Ti3C2Tx/TiO2 Composite Films: A Strategy for Photoelectrically Controllable Photocatalytic Degradation

The 2D Ti3C2Tx MXene has a large specific surface area, abundant functional groups, and low work function, which has potential in the field of photocatalytic materials. However, the manufacturing of controllable films with high photocatalytic properties and desirable transmittance is a challenging task. Herein, low‐cost, large‐scale, and rapid preparation of Ti3C2Tx/TiO2 flexible composite films have been successfully prepared by inkjet printing technology, which can be applied in complex and special environments, as well as in photoelectrically controllable places for photocatalytic performance. With the increase of the anatase TiO2, the transmittance of Ti3C2Tx/TiO2 films increases from 55.37% to 73.27% at 780 nm, corresponding to the square resistance of 1.112–206.496 kΩ sq−1 and the figure of merit of 0.48–0.005. When the amount of anatase TiO2 is 15%, the film has the best photocatalytic effect on methylene blue (MB) dye, reaching 68.94%. After five cycles of testing, the degradation efficiency of MB dye decreases by only 5.68%, showing that the film has good cycling stability. This work provides a new research direction for photoelectrically controllable photocatalytic degradation in complex and special environments.

Densification, phase composition, microstructure and properties of spark plasma sintered La0.6Ce0.3Pr0.1B6 bulks

This paper studied the densification, phase composition, microstructure and properties of polycrystalline La0.6Ce0.3Pr0.1B6 bulks prepared by SPS. The dense specimen (98.9 % in relative density) with the average grain size of 15.46 μm has been determined to be a CsCl-type single-phase substitutional solid solution without any impurities or other secondary phases. The homogenous elemental distributions of La, Ce and Pr have been confirmed by both microscale and nanoscale. The room temperature (RT) Vickers hardness (Hv), indentation fracture toughness (KIC) and flexure strength of the dense specimen have been measured to be 23.0 GPa, 2.04 MPa m1/2 and 305.1 MPa, respectively. The Berkovich hardness (HB) and elastic modulus (E) of the dense specimen have been measured to be 30.0 GPa and 376.0 GPa, respectively, by nanoindentation tests at a maximum load of 40 mN. In comparison with the polycrystalline LaB6 bulk, the lower work function Φ of 2.64 eV evaluated by UPS and the larger thermionic emission current densities measured at the same operating condition suggest that the polycrystalline La0.6Ce0.3Pr0.1B6 bulk is a superior-performance thermionic cathode material.

Silicon Clathrate-Supported Catalysts with Low Work Functions for Ammonia Synthesis.

Diamond-type silicon has a work function of ≈4.8eV, and conventional n- or p-type doping modifies the value only between 4.6 and 5.05eV. Here, it is shown that the alkali clathrates AxSi46 have substantially lower work functions approaching 2.6eV, with clear trends between alkali electropositivity and clathrate cage size. The low work function enables alkali clathrates such as K8Si46 to be effective Haber-Bosch catalyst supports for NH3 synthesis. The catalytic properties of Si, Ge, and Sn-based clathrates are investigated while supporting Fe and Ru on the surface. The activity largely scales with the work function, and low activation energies below 60kJ mol-1 are observed due to strong electron donation effects from the support. Ru metal and Sn clathrates seem to be unsuitable for stability issues. Compared to other similar hydride/electride catalysts, the simple structure and composition combined with stability in air/water make a systematic study of these clathrates possible and open the door to other electron-rich Zintl phases and related intermetallics as low-work function materials suitable for catalysis. The observed low work function may also have implications for other existing electronic applications.

Enhanced Electron Emission Performance and Air-Surface Stability in ScO-Terminated Diamond for Thermionic Energy Converters.

Diamond with negative electron affinity (NEA) and low work function surfaces are suggested as a suitable material for electron-generation applications in vacuum, in particular, as the emitter electrode in thermionic energy converters. Such NEA surfaces can be fabricated by evaporating and then annealing submonolayers of a suitable metal in vacuo onto bare or oxidized diamond. Among the metals studied, scandium termination of bare diamond (100) and (111) surfaces is recently reported to give the largest NEA values reported to date for a metal-diamond system, as well as being thermally stable to 900°C. It is now shown that preoxidized (100) diamond functionalized with 0.25monolayers of Sc also produces a large NEA value of -1.02eV with low work functions (<3.63eV). Moreover, this surface is thermally stable to 700°C and can withstand exposure to air for extended periods. Here, the structural and electronic properties of this Sc─O-functionalized diamond surface are characterized in detail using a variety of surface-science techniques. The results suggest that this material may be the ideal candidate for the fabrication of commercial thermionic energy conversion devices, e.g., for solar-power generation, as well as for various other electronic devices that rely upon electron emission.

Assessment of photovoltaic efficacy in antimony-based cesium halide perovskite utilizing transition metal chalcogenide

Antimony-based perovskites have been recognized for their distinctive optoelectronic attributes, standard fabrication methodologies, reduced toxicity, and enhanced stability. The objective of this study is to systematically investigate and enhance the performance of all-inorganic solar cell architectures by integrating Cs3Sb2I9, a perovskite-analogous material, with WS2—a promising transition metal dichalcogenide—used as the electron transport layer (ETL), and Cu2O serving as the hole transport layer (HTL). This comprehensive assessment extends beyond the mere characterization of material attributes such as layer thickness, doping levels, and defect densities, to include a thorough investigation of interfacial defect effects within the structure. Optimal efficiency was observed when the Cs3Sb2I9 absorber layer thickness was maintained within the 600-700 nm range. The defect tolerance for the absorber layer was identified at 1×1015/cm3, with the ETL and HTL layers exhibiting significant defect tolerance at 1×1016/cm3 and 1×1017/cm3, respectively. Furthermore, this study calculated the minority carrier lifetime and diffusion length, establishing a strong correlation with defect density; a minority carrier lifetime of approximately 1 µs was noted for a defect density of1×1014/cm3 in the absorber layer. A noteworthy finding pertains to the balance between the high work function of the back contact and the incorporation of p-type back surface field layers, revealing that interposing a highly doped p+ layer between the Cu2O and the metal back contact can elevate the efficiency to 21.60%. This approach also provides the freedom to select metals with lower work functions, offering a cost-effective advantage for commercial-scale applications.

Achievement of low turn-on voltage in Ga2O3 Schottky and heterojunction hybrid rectifiers using W/Au anode contact

The use of the low work function (4.5 eV) tungsten (W) as a rectifying contact was studied to obtain low on-voltages in W/Ga2O3 Schottky rectifiers and NiO/Ga2O3 heterojunction rectifiers that were simultaneously fabricated on a single wafer. The devices were produced with varying proportions of relative areas and diameters, encompassing a spectrum from pure Schottky Barrier Diode (SBD) to pure Heterojunction Diode (HJD) configurations. The turn-on voltages with W contacts ranged from 0.22 V for pure Schottky rectifiers to 1.50 V for pure HJDs, compared to 0.66 and 1.77 V, respectively, for Ni/Au contacts. The reverse recovery times ranged from 31.2 to 33.5 ns for pure Schottky and heterojunction rectifiers. Switching energy losses for the SBD with W contacts were ∼20% of those for HJDs. The reverse breakdown voltages ranged from 600 V for SBDs to 2400 V for HJDs. These are the lowest reported turn-on voltage values for 600/1200 V-class Ga2O3 rectifiers that extend the range of applications of these devices down to the voltages of interest for electric vehicle charging applications.

Low-cost deposition of tunable band gap Zn(O,S) as electron transport layer for crystalline silicon heterojunction solar cells

In recent years, the research on silicon heterojunction (HJT) solar cells based on dopant-free contacts has experienced rapid development. Zn(O,S) is a low work function n-type semiconductor compound with tunable band gap that can be used as the electron transport layer (ETL) in HJT solar cells. In our work, we choose Zn(O,S) as ETL and deposit it via the low-cost chemical bath deposition (CBD) method. Uniform and fast growth of Zn(O,S) films can be obtained by regulating the concentration of the complexing agent and the ratio of reactants to reduce the generation of impurities. To further achieve band matching with c-Si, the Zn(O,S) films are processed with air-annealing to modify the elemental ratios. The air-annealing lowers the interfacial electron transport barrier, which promotes charge separation and transport, thus reducing carrier recombination at the interface. Finally, the PCE of HJT solar cell based on CBD-Zn(O,S) ETL is close to 15 %, providing a new potential route for the development of low-cost HJT solar cells.

A vertically staged 2D van der Waals SnS2/SiS2 heterostructures for photovoltaic and photocatalytic application

This study investigates into the geometric, optical, and thermodynamic characteristics of the vertically staged 2D van der Waals SnS2/SiS2 heterostructure, examining its potential for photovoltaic and photocatalytic applications. A study of the band alignment reveals an indirect band-gap p-type semiconductor with a z-scheme configuration. The density of states highlights the significant influence of S-4p orbitals on the valence band near the Fermi level, while Sn/Si-3p orbitals contribute to the conduction band minimum. Furthermore, the SnS2/SiS2 heterostructure can control interlayer charge transport, impacting the band gap. Notably, the lower work function of the SnS2 layer facilitates the spontaneous migration of electrons from SnS2 to SiS2 within the heterostructure. These results, coupled with reduced work function and enhanced optical properties, emphasize the potential of this heterostructure as an efficient photocatalyst and photovoltaic material.

Harnessing the clean energy: Phosphorus-alkynyl covalent organic frameworks for photocatalytic hydrogen production

Given the diminishing reserves of fossil fuels, the development of renewable alternative energy sources is of global importance. Photocatalytic hydrogen (H2) evolution stands out as a promising and cost-effective method to harness sunlight for producing carbon-free H2 fuel. Recently, two-dimensional (2D) covalent organic frameworks (COFs) have garnered considerable research interest in photocatalysis on account of their exceptional surface area and predictable assembly of diverse molecules with adjustable electronic properties. Herein, six 2D COFs are constructed by topologically assembling phosphorus-alkynyl functional moieties and benzene-based building units, including benzene (COF-1), triazine (COF-2), heptazine (COF-3), triphenyl-benzene (COF-4), triphenyl-triazine (COF-5), and triphenyl-heptazine (COF-6), employing first-principles calculations. Our computational results illustrate that the variation of benzene-based building units significantly regulates the electronic structures of COFs, all of which possess semiconductor properties with tunable bandgaps spanning from 1.56 to 2.56 eV. Of particular importance, COF-1, COF-2, COF-4, COF-5, and COF-6 can spontaneously stimulate the hydrogen evolution reaction (HER) under their own light-induced bias without the need for sacrificial agents and co-catalysts. Among them, COF-4 and COF-5 show the best HER activity without light-induced bias, with ΔG values of 0.02 and −0.01 eV, respectively, whose excellent photocatalytic performance can be ascribed to their appropriate electronic band structures, pronounced optical absorption, and low work functions. This finding offers profound insights for exploring other highly efficient HER photocatalysts.

Enhanced Li-ion battery performance based on multisite oxygen vacancies in WO3-x@rGO negative electrode

While transition-metal oxides have emerged as promising candidates for lithium energy storage, several issues are remained to be addressed such as low conductivity, rate performance, and recyclability. In this study, a three-dimensional interconnected sheet-like heterostructure of WO3-x coated with reduced graphene oxide (rGO) was synthesized using the hydrothermal method. This structure significantly enhanced the conductivity of WO3-x. By combining the heterojunction with oxygen vacancies (OV), the active sites are enlarged, promoting the effective movement of ions and electrons at the interface between the WO3-x and rGO. The prepared anode exhibits a high specific capacity of 1202.6 mAh/g at 0.1 A g−1, with a cycling retention rate of 96 % after 100 cycles. Meanwhile, even at 5 A g−1, it still maintains a capacity of 305 mAh/g after 500 cycles. Theoretical calculations reveal that the presence of the composite heterogeneous structure enables WO3-x@rGO to possess appropriate adsorption energy, lower work function, and reduced barriers. This arrangement provides abundant active sites, promoting the rapid penetration of the electrolyte and enhancing the interface reaction kinetics, which is consistent with the experimental results. This study offers a new strategy for Li-ion anode materials.

A Polymeric Two-in-One Electron Transport Layer and Transparent Electrode for Efficient Indoor All-Organic Solar Cells.

Transparent electrodes (TEs) are vital in optoelectronic devices, enabling the interaction of light and charges. While indium tin oxide (ITO) has traditionally served as a benchmark TE, its high cost prompts the exploration of alternatives to optimize electrode characteristics and improve device efficiencies. Conducting polymers, which combine polymer advantages with metal-like conductivity, emerge as a promising solution for TEs. This work introduces a two-in-one electron transport layer (ETL) and TE based on films of polyethylenimine ethoxylated (PEIE)-modified poly(benzodifurandione) (PBFDO). These PEIE-modified PBFDO layers exhibit a unique combination of properties, including low sheet resistance (130 Ω sq-1), low work function (4.2 eV), and high optical transparency (>85% in the UV-vis-NIR range). In contrast to commonly used poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), the doping level of PBFDO remains unaffected by the PEIE treatment, as verified through UV-vis-NIR absorption and X-ray photoelectron spectroscopy measurements. When employed as a two-in-one ETL/TE in organic solar cells, the PEIE-modified PBFDO electrode exhibits performance comparable to conventional ITO electrodes. Moreover, this work demonstrates all-organic solar cells with record-high power conversion efficiencies of >15.1% under indoor lighting conditions. These findings hold promise for the development of fully printed, all-organic optoelectronic devices.

An on-demand source of nanoparticles for optomechanics

The generation of nanoparticles on demand, with good control over their size and shape, has been a challenge for nanotechnology and the rapidly growing field of levitated optomechanics. Here, we present the preparation, launch, and detection of single nanoparticles in both a buffer gas and in vacuum. A tightly focused ultrashort laser beam with low energy is used to melt, form, and release individual particles. Surface tension supports the creation of spherical particles from molten droplets whose radii can be controlled, here in the range r=80−200 nm, by varying the pulse energy. The particle source is compact and compatible with high vacuum. It can be applied equally to dielectrics and metals as demonstrated here for silicon and gold. The method is unique in its capability to generate pristine silicon spheres directly in vacuum, which would rapidly oxidize when formed in air. Silicon is of interest for levitated optomechanics, cavity cooling, and emerging quantum interference experiments because of its high infrared polarizability and its low work function. Combining the source with an infrared cavity, we characterize the launch velocity and transit dynamics for silicon and gold nanoparticles in a high-finesse cavity field.

Adsorption behaviour of transition metal atoms on pristine and defective two-dimensional MgAl2S4 monolayer

The electronic structures and magnetic properties of two-dimensional MgAl2S4 monolayer, as well as the adsorption configurations, adsorption energy, and charge transfer phenomena of transition metal atoms adsorbed on both pristine and defective monolayer MgAl2S4 surfaces were systematically investigated. The results show that MgAl2S4 at equilibrium is a nonmagnetic indirect semiconductor with a bandgap of 1.908 eV. The adsorption energies of the adsorbed structures on both pristine and defective MgAl2S4 surfaces are negative, indicating good stability for all configurations. The adsorption of transition metal atoms leads to the transformation of the MgAl2S4 monolayer from non-magnetic semiconductor to magnetic semiconductor, bipolar magnetic semiconductor, half-metal, and metal. In addition, there is a good modulation of the bandgap. The significant charge transfer between MgAl2S4 monolayer and the transition metal atoms implies the formation of chemical bonds. The lower work function implies that the MgAl2S4 and transition metal atom adsorption structures benefit electron emission. Thus, research has revealed that the adsorption configurations of transition metal atoms on the surface of MgAl2S4 monolayer offers new possibilities for the fabrication of spintronic devices, the design of highly efficient catalysts, and the application of emission devices.

Janus piezoelectric ZrSi[formula omitted]H ([formula omitted] N, P, As) semiconductors with Raman response and high carrier mobility by a first-principles investigation

Motivated by the growing demand for new materials with novel properties, in the present work we design a series of two-dimensional Janus ZrSiZ3H (Z= N, P, As) monolayers and examine their physical features by using first-principle investigations. All three ZrSiN3H, ZrSiP3H, and ZrSiAs3H monolayers have good thermodynamic and mechanical stabilities from the ab initio molecular dynamics and obtained elastic coefficients results. The ZrSiZ3H systems also exhibit Raman response and piezoelectricity. Among three monolayers, the ZrSiAs3H possesses the highest in-plane and extra out-of-plane piezoelectric effects with d11 and d31 values of −7.88 pm/V and −0.19 pm/V, respectively. In addition, from calculated band structures, the ZrSiZ3H systems are found as semiconductors with bandgap energies varying from 0.90 to 3.00 eV at the Heyd–Scuseria–Ernzerhof theoretical level. The Zr-d and P-p orbitals give significant contributions to the band edge formation of all proposed configurations. The electrons can escape more easily from the H side than from the Z side due to their lower work functions. Notably, the ZrSiZ3H structures show anisotropic carrier mobilities along two in-plane axes. The ZrSiP3H and ZrSiAs3H monolayers exhibit high electron mobility in the x direction of 6925.53 and 6291.17 cm2V−1s−1, respectively. Our findings highlight the ZrSiZ3H systems as stable piezoelectric and electronic semiconductors for technological applications.

Steep subthreshold swing Double - Gate tunnel FET using source pocket engineering: Design guidelines

In this work, we propose a promising source engineered Double - Gate (DG) Tunnel Field Effect Transistor (TFET) device capable of providing remarkably low value of Subthreshold Swing (SS) with sufficiently high drive current. Using Sentaurus TCAD simulations, we demonstrate that counter-doped horizontal pockets (doping of pocket is kept opposite to that of source) when placed in the source region introduces a built-in band bending at the source-pocket junction. This lowers the minima of Conduction Band (CB) in pocket region thereby reducing the barrier width as the pocket CB moves closer to source Valence Band (VB). As a result, stronger electric field is observed thereby reducing the threshold voltage (onset of band-to-band tunneling (BTBT)) and subsequent reduction in subthreshold swing. To boost the ON-current and suppress ambipolarity, high-k dielectric material along with low work-function gate material is introduced at source side and low-k gate dielectric along with high work-function gate material is introduced at drain side. Compared to point tunneling in conventional TFETs, the gate overlapped pockets in the proposed structure result in an increase in cross-section area available for BTBT thereby leading to line tunneling of carriers from the source to the pocket, resulting in higher ON-current. In this work, we discuss the role of source engineering in boosting the performance of Hetero-Dielectric (HD) Dual-Metal-Double-Gate (DMDG) TFET. We provide design guidelines to achieve steeper subthreshold swing while considering pocket doping and pocket thickness as the key parameters. A comparative study of conventional DG-TFET and HD-DG-TFET with the proposed Gate-over-Pockets (GoP) HD-DMDG-TFET structure is done. When compared to the conventional DG-TFET with same geometrical parameters, the proposed structure provides ∼33× steeper SS, more than two order improved ON-current, two order lower ambipolar current and 133 folds better Ion/Ioff thus becomes the perfect choice for low power applications.

Patterned flexible Silver Nanowire/2D MXene transparent conducting electrode for organic light-emitting diodes

With the advent of numerous flexible optoelectronic applications, the importance of flexible and stable transparent conducting electrodes (TCEs) has been considerable. The conventional silver nanowire (AgNW) is a promising candidate as TCEs due to its decent opto-electrical properties and solution processibility. However, AgNW's high surface root mean square (RMS) roughness, relatively high sheet resistance, and low work function (∼4.5 eV) limit the usage for display applications. In this work, we design and study the AgNW and MXene (Ti3C2Tx) hybrid TCEs for flexible organic light-emitting diodes (OLEDs) to enhance the optoelectrical properties and the hole injection within the device. Experiment investigation is carried out via an application of AgNW/MXene (AgMX) hybrid TCEs as a bottom electrode for OLEDs devices in which the photolithography process and lift-off technique are employed for such fabrication. The hybrid TCEs indicate high optical transparency (86.8 % at 550 nm) and low sheet resistance (24.1 Ω/cm2) as well as improved surface morphology, enabling the efficient OLEDs operation. The optimized OLEDs exhibit a clear and stable red electroluminescence (EL) peak with an improved maximum external quantum efficiency (EQE) and luminance of 5.25 % and 3421.7 cd/m2, respectively. Furthermore, the hybrid TCEs are readily formed on poly(ethylene terephthalate) (PET) substrate, showing high durability under the bending test up to 100,000 cycles. The results demonstrate that adopting AgMX TCEs is a reasonable strategy for obtaining proper flexible optoelectronic devices.

Laser powder bed fusion of in-situ amorphous oxide dispersion strengthened immiscible Cu-316 L bimetallic composite: Formation mechanism and current-carrying wear behavior

This work used laser powder bed fusion (LPBF) to successfully produce in-situ nanoscale amorphous oxide dispersion strengthened (AODS) immiscible Cu-316 L bimetallic composite. Due to high affinity of Cr and O and the high cooling rate of LPBF, the formation of in-situ nano-amorphous Cr-rich oxide particles can refine the γ-Fe particles embedded in ε-Cu matrix. Moreover, the γ-Fe particles have "shadow protection effect" on ε-Cu matrix, the wear mechanism is mechanical wear during low current-carrying wear (0–2 A). However, during high current-carrying wear (5 A and 7 A), arc erosion preferentially occurs on γ-Fe particles with lower work functions, which enhances arc erosion resistance of ε-Cu matrix. The wear mechanisms are dominated by electric-arc erosion and oxidation wear.