Lattice Mismatch Research Articles

Machine learning potential for the Cu-W system

Combining the excellent thermal and electrical properties of Cu with the high abrasion resistance and thermal stability of W, Cu-W nanoparticle-reinforced metal matrix composites and nano-multilayers are finding applications as brazing fillers and shielding material for plasma and radiation. Due to the large lattice mismatch between fcc Cu and bcc W, these systems have complex interfaces that are beyond the scales suitable for methods, thus motivating the development of chemically accurate interatomic potentials. Here, a neural network potential (NNP) for Cu-W is developed within the Behler-Parrinello framework using a curated training dataset that captures metallurgically relevant local atomic environments. The Cu-W NNP accurately predicts (i) the metallurgical properties (elasticity, stacking faults, dislocations, thermodynamic behavior) in elemental Cu and W, (ii) energies and structures of Cu-W intermetallics and solid solutions, and (iii) a range of fcc Cu/bcc W interfaces, and exhibits physically reasonable behavior for solid W/liquid Cu systems. As will be demonstrated in forthcoming work, this near accurate NNP can be applied to understand complex phenomena involving interface-driven processes and properties in Cu-W composites. Published by the American Physical Society 2024

Fabrication of 0.6 eV Bandgap In0.69Ga0.31As Thermophotovoltaic Cells and Its System Demonstration

Thermophotovoltaic (TPV) is a promising energy conversion technology that can absorb the heat from a thermal radiator and transfer it into power. As the most significant energy converter, TPV cells need a narrower bandgap to realize a wider absorption spectrum range. In this work, the fabrication and characterization of single‐junction In0.69Ga0.31As TPV cells with a bandgap of 0.6 eV are presented. The main structure is grown on an InP substrate through metal‐organic chemical vapor deposition. Step‐graded InAsyP1−y buffer layers are used to mitigate the dislocations by relaxing the stress induced by lattice mismatch completely. Analysis of the composition, strain relaxation, layer tilt, and crystalline quality of each layer is demonstrated using triple‐axis X‐ray reciprocal space mapping and transmission electron microscopy. According to the tested results, each layer is found to be nearly fully relaxed and the InGaAs active layer grown on the buffer displays a high crystal quality. External quantum efficiency achieves 90% at 1100–1500 nm. Additionally, a TPV test platform is constructed to evaluate the cell performance. The maximum efficiency of the lattice‐mismatched TPV cell reaches 21.92% operating at a power density of 267.4 mW cm−2 and an emitter temperature of 1200 °C.

Fabrication of Ultrathin Ferroelectric Al0.7Sc0.3N Films under Complementary-Metal-Oxide-Semiconductor Compatible Conditions by using HfN0.4 Electrode.

Aluminum scandium nitride (AlScN) has emerged as a promising candidate for next-generation ferroelectric memories, offering a much higher remanent charge density than other materials with a stable ferroelectric phase. However, the inherently high coercive field requires a substantial decrease in film thickness to lower the operating voltage. Significant leakage currents present a severe challenge during the thickness scaling, especially when maintaining compatibility with complementary-metal-oxide-semiconductor (CMOS) fabrication standards. This study adopts a HfN0.4 bottom electrode, which minimizes lattice mismatch with Al0.7Sc0.3N (ASN), forming a coherent bottom interface that effectively reduces leakage currents even at thickness <5nm. CMOS-compatible HfN0.4/ASN/TiN stack, deposited without vacuum break between each layer, demonstrates exceptional scalability, confirming the ferroelectricity of ASN films at thicknesses down to 3nm. The coercive voltage is decreased to 4.35V, significantly advancing low-voltage AlScN devices that align with CMOS standards.

Improvement of the magnetization and heating ability of CoFe2O4/ NiFe2O4 core/shell nanostructures

Abstract In this study, the effect of the shell thickness on the structural and magnetic properties of the CoFe2O4/NiFe2O4 core/shell is studied. A single-phase core/shell nanocomposite was prepared by the hydrothermal method. The shell thickness was found to control the magnitudes of saturation magnetization and coercive field of the prepared samples. The thickness of the NiFe2O4, which covered cubic CoFe2O4 particles of 15 nm, was 1.8 nm, leading to an increase in the saturation magnetization by 26% and a decrease in the coercive field by 50% compared to bare CoFe2O4. However, a further increase in shell thickness caused interfacial dislocations due to the lattice mismatch between the core and the shell. Finally, the heating ability at high frequency was measured for all samples. Comparing the temperature rise under the influence of AC magnetic field, which indicates power loss, relative to bare CoFe2O4, it was enhanced by 100% for a shell thickness of 26 nm. The results of this study point to potential applications for these samples in the field of magnetic hyperthermia for cancer therapy and drug delivery.&amp;#xD;

High-Performance Ga2O3 Solar-Blind Photodetector Based on Thermal Oxidized Ga Buffer-Layer.

High-performance Ga2O3 solar-blind photodetectors are critical for applications due to their selective solar-blind ultraviolet sensitivity. The quality of the Ga2O3 film has a significant impact on the performance of photodetectors. This study presents an innovative approach to enhancing the quality of Ga2O3 films through the introduction of a naturally graded buffer layer, which is formed by the oxidation of a metallic Ga film and significantly improves interface stability by accommodating lattice mismatches and reducing defects. The structural and compositional characteristics of Ga2O3 films were comprehensively analyzed using UV-vis (ultraviolet-visible) spectroscopy, AFM (Atomic Force Microscope), PL (Photoluminescence Spectroscopy), TEM (Transmission Electron Microscope), and XPS (X-ray Photoelectron Spectroscopy). The photodetectors fabricated from these films demonstrate responsivity of 99.8 mA/W and a solar-blind UV/UV ratio of 1.17 × 103, with significant improvement compared to direct deposited films. This research highlights the potential of natural buffering layers to advance the performance of Ga2O3-based solar-blind UV detectors.

Depth Profiles of Crystallinity and Preferential Orientation and Surface Characteristics of Sputter‐Deposited CeO2 Thin Film Buffer Layers on Sapphire Substrates Evaluated Through Two‐Dimensional Grazing‐Incidence X‐Ray Diffraction

ABSTRACTTwo‐dimensional grazing‐incidence wide‐angle X‐ray diffraction data were acquired from CeO2 thin films serving as buffer layers on r‐cut sapphire substrates to investigate the depth profiles of crystallinity and preferential orientation as well as surface conditions. The thin film samples were sputter‐deposited under different conditions. Data were obtained at an X‐ray wavelength of 0.100 nm at 0.02° intervals from 0.06° to 0.30° at the grazing‐incidence angle. A 60‐nm‐thick CeO2 thin film sputter‐deposited under Ar (Ar‐60) and a 100‐nm‐thick CeO2 thin film sputter deposited using 10 vol.% O2 in Ar (O+Ar‐100) were found to have partially oriented three‐dimensional bulk crystal structures with preferential orientation in the (100) direction near the surface. The lattice constant for the Ar‐60 film was found to be approximately 0.30% smaller than that for a CeO2 standard, whereas the lattice constant for the O+Ar‐100 film was approximately 0.50% larger. Lattice mismatch between the CeO and CeO2 on the substrate surface is evidently not an issue based on the lattice constants near the surface. Hence, both films could be considered to represent optimal buffer layers for YBa2Cu3O6+δ thin film growth. However, even in the case of a CeO2 thin film suitable for use as a buffer layer, the difference in lattice constants between the interior and surface of an Ar‐60 film was found to be relatively small, whereas that for an O+Ar‐100 film was relatively large. These results show that it is important to analyze the film surface in detail by reducing the incidence angle to less than 0.1°.

Regulation of Interface Compatibility and Performance in Soft Magnetic Composites with Inorganic Insulation Layers by FePO4 Intermediate Transition Layer

In the fabrication of soft magnetic composites, the lattice mismatch between the inorganic insulation layer and the iron matrix often leads to the formation of cracks during the molding process, which significantly impairs the operational performance of the materials. Consequently, it is imperative to develop novel strategies for inorganic insulation coatings that offer high electrical resistivity and thermal stability and are less susceptible to cracking during formation. This paper presents a new structure for soft magnetic composites that incorporates FePO4 as an intermediate transition layer between the iron-based soft magnetic particles and the inorganic ceramic insulation layer. This configuration is designed to provide insulation coatings with superior voltage and thermal resistance, as well as high electrical resistivity. The research details the processes forming the FePO4 intermediate transition layer and the SiO2 insulation layer on the iron powder surface, along with their interaction mechanisms. An analysis comparing the scenarios with and without the FePO4 intermediate transition layer shows its beneficial impact on the magnetic properties and mechanical strength of the soft magnetic composites. Further investigations reveal that at a phosphoric acid concentration of 1 wt.%, the FePO4 layer significantly enhances the interface compatibility between the Fe powder matrix and the SiO2 insulation layer. Under these conditions, the Fe@ FePO4/SiO2 soft magnetic composites demonstrate outstanding overall performance: the saturation magnetization stands at 215.60 emu/g, effective permeability at 83.2, resistivity at 57.42 Ω·m, power loss at 375.0 kW/m3 under 30 mT/100 kHz, and radial compressive strength at 15.95 Kgf. These findings offer novel insights and practical approaches for advancing inorganic insulation coating strategies and provide vital scientific support for further enhancing the magnetic and mechanical properties of soft magnetic composites.

Three‐Dimensional (3D) Fluoride Molecular Glue to Improve the SnO2/Perovskite Interface for Efficient Perovskite Solar Cells

AbstractAiming at numerous defects at SnO2/perovskite interface and lattice mismatch in perovskite solar cells (PSCs), we design a kind of three‐dimensional (3D) molecular glue (KBF4‐TFMSA), which is derived from strong intramolecular hydrogen bonding interaction between potassium tetrafluoroborate (KBF4) and trifluoromethane‐sulfonamide (TFMSA). A remarkable efficiency of 25.8 % with negligible hysteresis and a stabilized power output of 25.0 % have been achieved, in addition, 24.57 % certified efficiency of 1 cm2 device is also obtained. Further investigation reveals that this KBF4‐TFMSA can interact with oxygen vacancies and under‐coordinated Sn(IV) from the SnO2, in the meantime, FA+ (NH2−C=NH2+) and K+ cations can be well fixed by hydrogen bonding interaction between FA+ and BF4−, and electrostatic attraction between sulfonyl oxygen and K+ ions, respectively. Thereby, FAPbI3 crystal grain sizes are increased, interfacial defects are significantly reduced while carrier extraction/ transportation is facilitated, leading to better cell performance and excellent stabilities. Non‐encapsulated devices can maintain 91 % of their initial efficiency under maximum‐power‐point (MPP) tracking while continuous illumination (~100 mW cm−2) for 1000 h, and retain 91 % of the initial efficiency after 1000 h “double 60” damp‐heat stability testing (60 °C and 60 %RH (RH, relatively humidity)).

Introducing boron gallium nitride as carriers’ source layer for efficient near-ultraviolet microLED

Abstract This study explored the impact of boron gallium nitride (BGaN) in buffer layer and hole source layer. We employed B0.05Ga0.95N which reduced the lattice mismatch as well as the electric field. BGaN not only minimized the number of electrons leaking out of quantum wells (QWs) but also improved the hole injection. It is evident from our simulations that internal quantum efficiency (IQE) is enhanced significantly as more carriers are available for radiative recombination in multiple quantum wells (MQWs). Along with the increase in IQE, droop is also reduced in BGaN ultraviolet light-emitting diodes. Significantly high luminous power and emission intensity were observed along with slight blueshift because of minimized quantum confinement stark effect (QCSE).

The tensile behaviors of Ag-Cu alloys with different Cu contents: Molecular dynamics simulations study

The Ag-Cu alloys have received attention due to their excellent electrical and mechanical properties. However, the analytical research on why the mechanical properties of the Ag-Cu alloys increase after a small amount of Cu atoms are added is still lacked. In this work, the classical molecular dynamics (MD) simulations method was used to establish the Ag-Cu alloy models with different Cu contents. The tensile deformation mechanism of Ag-Cu alloy at room temperature was revealed from the atomic scale through the analysis of the stress-strain behavior and the evolution of dislocations. During the simulations, the embedded atom method (EAM) potential was used to describe the interaction between Ag atom and Cu atom. The uniaxial tensile deformation and nanostructure evolution of Ag-3 at.% Cu, Ag-6 at.% Cu and Ag-10 at.% Cu alloy models at the temperature of 300 K and the strain rate of 0.02 Å/ps were studied in detail. Results show that the internal stress was generated due to the large lattice mismatch among Ag atom, Cu cluster and the grain boundary. It results in the formation of dislocation and the negative initial stress at the beginning stage of Ag-Cu alloy models under tension. The dislocation firstly nucleates at the grain boundary and the growth rate of dislocation is slow before the crack propagation, and the complex dislocation reactions also exist. With the increase of Cu content, the tensile strengths of Ag-Cu alloys also increase. Cracks mainly form at the intersection of multiple grains, and the fracture mode changes from the intergranular fracture to the intergranular fracture and transgranular fracture after the unstable propagation of cracks. Meanwhile, a plenty of Cu atoms are distributed in the form of clusters in Ag matrix. They hinder the slip of dislocation and slow the relative sliding between atomic layers, and thus finally improves the deformation resistance to the plastic deformation of Ag-Cu alloy. The study on the tensile deformation behavior of Ag-Cu alloy at room temperature has certain guiding significance for the practical production and application of the design of Ag-Cu alloy.

Synthesis of layered Co9S8-based composites for high-efficiency rotating evaporation of saturated brine

Harvesting freshwater via solar interfacial evaporation is a promising strategy with net-zero emissions. To achieve long-term stable freshwater acquisition, researchers have developed dynamic solar-driven water evaporators. However, these evaporators exhibit limited evaporation rates due to the insufficient photothermal conversion properties of the materials used. In this study, we prepared Co9S8/CoNiO2/Au composite materials through in-situ topological transformation, thereby improving the effect of the heterogeneous crystal lattice mismatch on electron transport. By embedding these materials into a spherical polyurethane sponge, we developed a new type of self-rotating evaporator with a solar full-spectrum absorbance of 95.84 %. The evaporator stably exhibited an evaporation rate of 3.10 kg m−2 h−1 within 240 h in saturated brine. The present work provides insights into the preparation of photothermal composites and the development of high-efficiency stable solar evaporators.

Atomic-scale insights into the microstructure and interface evolution mechanism of copper/tantalum nanofilms during ultra-precision grinding

The copper (Cu)/tantalum (Ta) nanofilms are the vital component in the through silicon via (TSV) wafer. However, the current lack of research on the ultra-precision machining of Cu/Ta nanofilms limits the development of TSV-based 3D integration technologies. In this work, molecular dynamics simulations are conducted to reveal the microstructure and interface evolution mechanism of Cu/Ta nanofilms during nano-grinding under various grinding depths. The results show that the material removal mode differs between the Cu and Ta layers, and the thickness of the subsurface damage layer of the Cu layer is greater than that of the Ta layer. The Cu/Ta interface is well stabilized, and small amounts of micro-defects appear only at larger grinding depths after grinding. The lattice mismatch of the constituent layers and the hindering role by the interface lead to stress concentration at the interface, and it is more obvious with increasing grinding depth. Nevertheless, there is a significant stress release after grinding. Our computations indicate that the competition between the evolution of interfacial structures and discrepancies in the physical properties of constituent layers leads to an increase in grinding forces at the interface. Furthermore, the heat transfer is obstructed by the Cu/Ta interface. This study provides valuable insights into the grinding mechanisms of Cu/Ta nanofilms, which is conducive to further improving the manufacturing process of the TSV wafer and enhancing the performance of microelectronic devices.

Low Hysteresis Vanadium Dioxide Integrated on Silicon Using Complementary Metal‐Oxide Semiconductor Compatible Oxide Buffer Layer

VO2 undergoes a metal‐insulator transition (MIT) at ≈70 °C, which induces large variations in its electrical and wavelength‐dependent optical properties. These features make VO2 a highly sought‐after compound for optical, thermal, and neuromorphic applications. To foster the development of VO2‐based devices for the microelectronic industry, it is also imperative to integrate VO2 on silicon. However, high lattice mismatch and the formation of silicates at the interface between VO2 and Si degrade the quality and functionality of VO2 films. Moreover, VO2's polymorphic nature and stable VO phases pose integration issues. To address these challenges, the MIT of VO2 thin films integrated on Si with a complementary metal‐oxide semiconductor‐compatible HfxZr1−xO2 (HZO) buffer layer is investigated. Using in situ high‐resolution X‐ray diffraction and synchrotron far‐infrared spectroscopy, combined with multiscale atomic and electronic structure characterizations, it is demonstrated that VO2 on the HZO buffer layer exhibits an unusually low thermal hysteresis of ≈4 °C. In these results, the influence of strain on M2 phase nucleation, which controls the hysteresis, is unraveled. Notably, the rate of phase transition is symmetric and does not change for the heating and cooling cycles, implying no incorporation of defects during cycling, and highlighting the potential of an HZO buffer layer for reliable operation of VO2‐based devices.

Imprinted atomic displacements drive spin–orbital order in a vanadate perovskite

AbstractPerovskites with the generic composition ABO3 exhibit an enormous variety of quantum states, such as orbital order, magnetism and superconductivity. Their flexible and comparatively simple structure allows for straightforward chemical substitution and cube-on-cube combination of different compounds in atomically sharp epitaxial heterostructures. Many of the diverse physical properties of perovskites are determined by small deviations from the ideal cubic perovskite structure, which are challenging to control. Here we show that directional imprinting of atomic displacements in the antiferromagnetic Mott insulator YVO3 can be achieved by depositing epitaxial films on different facets of the same isostructural substrate. These facets were chosen such that other well-known control parameters, including lattice and polarity mismatch with the overlayer, remain nearly unchanged. We observe signatures of staggered orbital and magnetic order and demonstrate distinct spin–orbital ordering patterns on different facets. We attribute these results to the influence of specific octahedral rotation and cation displacement patterns, which are imprinted by the substrate facet, on the covalency of the bonds and the superexchange interactions in YVO3. Our results show that substrate-induced templating of lattice distortion patterns constitutes a pathway for materials design beyond established strain-engineering strategies.

Scanning tunneling microscopy of ultrathin indium intercalated between graphene and SiC using confinement heteroepitaxy

Large-scale and air-stable two-dimensional metal layers intercalated at the interface between epitaxial graphene and SiC offer an appealing material for quantum technology. The atomic and electronic details, as well as the control of the intercalated metals within the interface, however, remain very limited. In this Letter, we explored ultrathin indium confined between graphene and SiC using cryogenic scanning tunneling microscopy, complemented by first-principle density functional theory. Bias-dependent imaging and tunneling spectroscopy visualize a triangular superstructure with a periodicity of 14.7 ± 3 Å and an occupied state at about −1.6 eV, indicating proof of highly crystalline indium. The scanning tunneling microscopy tip was used to manipulate the number of indium layers below graphene, allowing to identify three monatomic In layers and to tune their corresponding electronic properties with atomic precision. This further allows us to attribute the observed triangular superstructure to be solely emerging from the In trilayer, tentatively explained by the lattice mismatch induced by lattice relaxation in the topmost In layer. Our findings provide a microscopic insight into the structure and electronic properties of intercalated metals within the graphene/SiC interface and a unique possibility to manipulate them with atomic precision using the scanning probe technique.

First-Principles Calculations on Relative Energetic Stability, Mechanical, and Thermal Properties of B2-AlRE (RE = Sc, Y, La-Lu) Phases

The relative energetic stability, mechanical properties, and thermodynamic behavior of B2-AlRE (RE = Sc, Y, La-Lu) second phases in Al alloys have been investigated through the integration of first-principles calculations with the quasi-harmonic approximation (QHA) model. The results demonstrate a linear increase in the calculated equilibrium lattice constant a0 with the ascending atomic number of RE, while the enthalpy of formation ΔHf exhibits more fluctuating variations. The lattice mismatch δ between B2-AlRE and Al matrix is closely correlated with the transferred electron et occurring between Al and RE atoms. Furthermore, the mechanical properties of the B2-AlRE phases are determined. It is observed that the calculated elastic constants Cij, bulk modulus BH, shear modulus GH, and Young’s modulus EH initially decrease with increasing atomic number from Sc to Ce and then increase up to Lu. The calculated Cauchy pressure C12-C44, Pugh’s ratio B/G, and Poisson’s ratio ν for all AlRE particles exhibit a pronounced directional covalent characteristic as well as uniform deformation and ductility. With the rise in temperature, the calculated vibrational entropy (Svib) and heat capacity (CV) of AlRE compounds exhibit a consistent increasing trend, while the Gibbs free energy (F) shows a linear decrease across all temperature ranges. The expansion coefficient (αT) sharply increases within the temperature range of 0~300 K, followed by a slight change, except for Al, AlHo, AlCe, and AlLu, which show a linear increase after 300 K. As the atomic number increases, both Svib and CV increase from Sc to La before stabilizing; however, F initially decreases from Sc to Y before increasing up to La with subsequent stability. All thermodynamic parameters demonstrate similar trends at lower and higher temperatures. This study provides valuable insights for evaluating high-performance aluminum alloys.

Facile Synthesis of Rhodium-Based Nanocrystals in a Metastable Phase and Evaluation of Their Thermal and Catalytic Properties.

Controlling the polymorphism of metal nanocrystals is a promising strategy for enhancing properties and discovering new phenomena. However, previous studies on Rh nanocrystals have focused on their thermodynamically stable face-centered-cubic (fcc) phase. Herein, a facile synthesis of Rh-based nanocrystals featuring the metastable hexagonal close-packed (hcp) phase is reported by using Ru seeds in their native hcp phase to template the deposition of Rh atoms. The success of such phase-controlled synthesis relies on the templating effect promoted by the small lattice mismatch between Ru and Rh and the slow dropwise titration of the precursor at an elevated temperature, ensuring the layer-by-layer growth mode and thus the formation of a conformal hcp-Rh shell. Faster injection rate of Rh(III) precursor leads to the formation of a rough Rh shell in the conventional fcc phase due to accelerated reaction kinetics. Considering both thermodynamic and kinetic aspects of this system, the hcp-Rh phase is favored when the low surface energy from smooth overlayers balances the high bulk energy of the metastable phase, achieved through tight control of reaction rates and deposition patterns. These Ruhcp@Rhhcp core-shell nanocrystals demonstrate thermal stability up to 400°C, while exhibiting higher catalytic activity toward ethanol oxidation reaction compared to Ruhcp@Rhfcc counterparts.

Toward crack-free AlN growth on silicon (111) by introducing boron incorporated buffer layer via MOCVD

High-quality aluminum nitride (AlN) films on silicon substrates are crucial for various applications due to their inherent properties as wide-bandgap semiconductors, cost-effectiveness, and compatibility with silicon-based circuits. Nonetheless, producing high-quality and crack-free AlN on silicon presents significant challenges due to the stress caused by lattice and thermal expansion mismatches. This study introduces a method to mitigate these challenges by incorporating a boron precursor during the metalorganic chemical vapor deposition process to form a BAlN buffer layer. Analytical techniques, such as secondary ion mass spectrometry, atomic force microscopy imaging, XRD rocking curves, reciprocal space map, and Raman spectroscopy, indicate that the BAlN buffer layer promotes the enlargement of seed crystal size, which effectively delays AlN coalescence, mitigates accumulated tensile stress, and enhances the overall crystal quality. Employing this technique has produced a 520 nm thick, crack-free AlN film on silicon (111) with high crystal quality, achieving full width at half maximum values of only 0.2° and 0.3° for XRC (002) and (102), respectively.

Highly Reversible Zn Anode Design Through Oriented ZnO(002) Facets.

The practical implementation of aqueous Zn-ion batteries presents formidable hurdles, including uncontrolled dendrite growth, water-induced side reactions, suboptimal Zn metal utilization, and intricate Zn anode manufacturing. Here, large-scale construction of a highly oriented ZnO(002) lattice plane on Zn anode (ZnO(002)@Zn) with thermodynamic inertia and kinetic zincophilicity is designed to address such problems. Both theoretical calculations and experiment results elucidate that the ZnO(002)@Zn possesses high Zn chemical affinity, hydrogen evolution reaction suppression, and dendrite-free deposition ability due to the abundant lattice oxygen species in ZnO(002) and its low lattice mismatch with Zn(002). These features synergistically promote ion transport and enable homogeneous Zn deposition. Consequently, the ZnO(002)@Zn anode displays a stable and prolonged cycling lifespan exceeding 500h even under a larger depth of discharge (85.6%) and realizes an impressive average Coulombic efficiency of 99.7%. Moreover, its efficacy is also evident in V2O5-cathode coin cells and pouch cells with not only high discharge capacity but also exceptional cycling stability. This integrated approach presents a promising avenue for addressing the challenges associated with Zn metal anodes, thereby advancing the prospects of aqueous Zn-ion battery technologies.

Lattice Match-Enabled Covalent Heterointerfaces with Built-in Electric Field for Efficient Hydrogen Peroxide Photosynthesis.

Crafting semiconducting heterojunctions represents an effective route to enhance photocatalysis by improving interfacial charge separation and transport. However, lattice mismatch (δ) between different semiconductors can significantly hinder charge dynamics. Here, meticulous lattice tailoring is reported to create a covalent heterointerface with a built-in electric field (BIEF), imparting markedly improved hydrogen peroxide (H2O2) photosynthesis. Specifically, an In2S3/CdS heterojunction with a coherent heterointerface, characterized by covalent In─S─Cd bridge and exceptionally low lattice mismatch of 0.27%, and a BIEF from In2S3 to CdS, is rationally designed. This heterojunction entails rapid charge separation and transfer, achieving an outstanding H2O2 production rate of 2.09 mmol g-1 h-1 without the need for scavengers and oxygen bubbling, and a high apparent quantum efficiency of 17.73% at 400 nm. Density functional theory (DFT) calculations further reveal that this Z-scheme heterojunction facilitates the adsorption of *O2 and the generation of *OOH intermediates during the 2e- oxygen reduction reaction, associated with a low Gibbs free energy. This study underscores the significance of fine-tuning interfacial lattices and integrating BIEF to accelerate photocatalysis. The simple yet robust strategy can be conveniently leveraged to enhance device performance in optoelectronics, electrocatalysis, photoelectrocatalysis, and sensing.