Showing papers on "Epitaxy published in 2022"

Epitaxial BiP5O14 layer on BiOI nanosheets enhancing the photocatalytic degradation of phenol via interfacial internal-electric-field

Abstract: BiOI/BiP5O14 heterostructure with enhanced interfacial internal electric field for directional charge transfer and separation effectively were constructed successfully through epitaxial BiP5O14 layer on the surface of BiOI nanosheets. Dramatical enhanced internal electric field of BiOI/BiP5O14 heterostructure was established when BiP5O14 monolayer epitaxial grow on the surface of BiOI nanosheets by adding 2% of NaH2PO4. As a result, this heterostructure could boost the photodegradation and mineralization of phenol. Compared to pristine BiOI nanosheets, the photocatalytic reaction constant rates of phenol over the BiOI/BiP5O14 heterostructure were elevated over 8.5 times, and the corresponding mineralization ability was also enhanced 8.9 times due to the effective and directional charges transfer and separation. This work provides an evidential proof of rational designing heterostructure via epitaxial growth, and confirms the internal electric field drive charge transfer and separation directionally for promoted photocatalytic performances.

A Robust Memristor Based on Epitaxial Vertically Aligned Nanostructured BaTiO3−CeO2 Films on Silicon

Abstract: With the exploration of ferroelectric materials, researchers have a strong desire to explore the next generation of non‐volatile ferroelectric memory with silicon‐based epitaxy, high‐density storage, and algebraic operations. Herein, a silicon‐based memristor with an epitaxial vertically aligned nanostructures BaTiO3–CeO2 film based on La0.67Sr0.33MnO3/SrTiO3/Si substrate is reported. The ferroelectric polarization reversal is optimized through the continuous exploring of growth temperature, and the epitaxial structure is obtained, thus it improves the resistance characteristic, the multi‐value storage function of five states is achieved, and the robust endurance characteristic can reach 109 cycles. In the synapse plasticity modulated by pulse voltage process, the function of the spiking‐time‐dependent plasticity and paired‐pulse facilitation is simulated successfully. More importantly, the algebraic operations of addition, subtraction, multiplication, and division are realized by using fast speed pulse of the width ≈50 ns. Subsequently, a convolutional neural network is constructed for identifying the CIFAR‐10 dataset, to simulate the performance of the device; the online and offline learning recognition rate reach 90.03% and 92.55%, respectively. Overall, this study paves the way for memristors with silicon‐based epitaxial ferroelectric films to realize multi‐value storage, algebraic operations, and neural computing chip applications.

Strain Adjustment Realizes the Photocatalytic Overall Water Splitting on Tetragonal Zircon BiVO4

Abstract: Overall water splitting to generate H2 and O2 is vital in solving energy problem. It is still a great challenge to seek efficient visible light photocatalyst to realize overall water splitting. In this work, the tetragonal zircon BiVO4 is prepared by epitaxial growth on FTO substrate and its overall water splitting reaction is studied. Under the influence of epitaxial strain, the conduction band position shifts negatively and beyond H+/H2 reduction potential (0 V vs NHE), which enables it to possess the photocatalytic hydrogen evolution activity. After loading cocatalysts, the overall water splitting (λ > 400 nm) is realized (H2: ≈65.7 µmol g−1 h−1, O2: ≈32.6 µmol g−1 h−1), and the value of solar hydrogen conversion efficiency is 0.012%. The single‐particle photoluminescence (PL) spectra and PL decay kinetics tests demonstrate the cocatalysts are beneficial to the separation and transfer of carriers. The new strategy of adjusting the band structure by strain is provided.

Epitaxial Growth of Vertically Aligned Antimony Selenide Nanorod Arrays for Heterostructure Based Self‐Powered Photodetector

Abstract: Antimony selenide (Sb2Se3) has garnered significant attention with its extraordinary optical and optoelectronic properties for optical and optoelectronic devices such as broadband photodetectors. The trends emerge in the synthesis of Sb2Se3 over a semiconducting substrate for the direct formation of heterostructures, which facilitate a pn junction for self‐powered photodetector. 1D Sb2Se3 nanorods are preferred to boost the charge carrier transport along the longitudinal direction as well as the optical absorption by light trapping. Great challenges remain for the vertical growth of nanorods. In this work, the precisely vertical alignment of Sb2Se3 nanorod arrays has been achieved in an epitaxial growth manner by selecting a lattice‐matching substrate, namely, boron‐doped ZnO (110) surface. The directly grown boron‐doped ZnO/Sb2Se3 nanorod arrays heterostructure leads to a high‐performance broadband photodetector. Eventually, the device demonstrates extraordinary figure‐of‐merit parameters, i.e., responsivity, on/off ratio, and specific detectivity. Furthermore, device simulation predicts the theoretical limit of the photodetector performances on the condition of suppressed defect density of the Sb2Se3. These results may shed light on the investigation of controlled growth of low‐dimensional materials, self‐powered photodetectors, and related optic and optoelectronic devices.

Red InGaN micro-light-emitting diodes (>620 nm) with a peak external quantum efficiency of 4.5% using an epitaxial tunnel junction contact

Abstract: We present efficient red InGaN 60 × 60 μm2 micro-light-emitting diodes ( μLEDs) with an epitaxial tunnel junction (TJ) contact. The TJ was grown by metal-organic chemical vapor deposition using selective area growth. The red TJ μLEDs show a uniform electroluminescence. At a low current density of 1 A/cm2, the emission peak wavelength is 623 nm with a full-width half maximum of 47 nm. The peak external quantum efficiency (EQE) measured in an integrating sphere is as high as 4.5%. These results suggest a significant progress in exploring high efficiency InGaN red μLEDs using TJ technology.

Review of Highly Mismatched III-V Heteroepitaxy Growth on (001) Silicon

Abstract: Si-based group III-V material enables a multitude of applications and functionalities of the novel optoelectronic integration chips (OEICs) owing to their excellent optoelectronic properties and compatibility with the mature Si CMOS process technology. To achieve high performance OEICs, the crystal quality of the group III-V epitaxial layer plays an extremely vital role. However, there are several challenges for high quality group III-V material growth on Si, such as a large lattice mismatch, highly thermal expansion coefficient difference, and huge dissimilarity between group III-V material and Si, which inevitably leads to the formation of high threading dislocation densities (TDDs) and anti-phase boundaries (APBs). In view of the above-mentioned growth problems, this review details the defects formation and defects suppression methods to grow III-V materials on Si substrate (such as GaAs and InP), so as to give readers a full understanding on the group III-V hetero-epitaxial growth on Si substrates. Based on the previous literature investigation, two main concepts (global growth and selective epitaxial growth (SEG)) were proposed. Besides, we highlight the advanced technologies, such as the miscut substrate, multi-type buffer layer, strain superlattice (SLs), and epitaxial lateral overgrowth (ELO), to decrease the TDDs and APBs. To achieve high performance OEICs, the growth strategy and development trend for group III-V material on Si platform were also emphasized.

An Epitaxial Ferroelectric ScAlN/GaN Heterostructure Memory

Abstract: Electrically switchable bistable conductance that occurs in ferroelectric materials has attracted growing interest due to its promising applications in data storage and in‐memory computing. Sc‐alloyed III‐nitrides have emerged as a new class of ferroelectrics, which not only enable seamless integration with III‐nitride technology but also provide an alternative solution for CMOS back end of line integration. In this paper, the resistive switching behavior and memory effect in an ultrawide‐bandgap, high Curie temperature, fully epitaxial ferroelectric ScAlN/GaN heterostructure is reported for the first time. The structure exhibits robust ON and OFF states that last for months at room temperature with rectifying ratios of 60–210, and further shows stable operation at high temperatures (≈670 K) that are close to or even above the Curie temperature of most conventional ferroelectrics. Detailed studies suggest that the underlying mechanism is directly related to a ferroelectric field effect induced charge reconstruction at the hetero‐interface. The robust resistive switching landscape and the electrical polarization engineering capability in the polar heterostructure, together with the promise to integrate with both silicon and GaN technologies, can pave the way for next‐generation memristors and further enable a broad range of multifunctional and cross‐field applications.

Epitaxially Grown Ru Clusters–Nickel Nitride Heterostructure Advances Water Electrolysis Kinetics in Alkaline and Seawater Media

Abstract: The epitaxial heterostructure can be rationally designed based on the in-situ growth of two compatible phases with lattice similarity, in which the modulated electronic states and tuned adsorption behaviors are conducive to the enhancement of electrocatalytic activity. Herein, theoretical simulations first disclose the charge transfer trend and reinforced inherent electron conduction around the epitaxial heterointerface between Ru clusters and Ni3N substrate (cRu-Ni3N), thus leading to the optimized adsorption behaviors and reduced activation energy barriers. Subsequently, the defect-rich nanosheets with the epitaxially grown cRu-Ni3N heterointerface are successfully constructed. Impressively, by virtue of the superiority of intrinsic activity and reaction kinetics, such unique epitaxial heterostructure exhibits remarkable bifunctional catalytic activity toward electrocatalytic OER (226 mV @ 20 mA cm-2) and HER (32 mV @ 10 mA cm-2) in alkaline media. Furthermore, it also shows great application prospect in alkaline freshwater and seawater splitting, as well as solar-to-hydrogen integrated system. This work could provide beneficial enlightenment for the establishment of advanced electrocatalysts with epitaxial heterointerfaces.

Facets-Directed Epitaxially Grown Lead Halide Perovskite-Sulfobromide Nanocrystal Heterostructures and Their Improved Photocatalytic Activity.

Abstract: Lead halide perovskite nanocrystal heterostructures have been extensively studied in the recent past for improving their photogenerated charge carriers mobility. However, most of such heterostructures are formed with random connections without having strong evidence of epitaxial relation. Perovskite-chalcohalides are the first in this category, where all-inorganic heterostructures are formed with epitaxial growth. Going beyond one facet, herein, different polyhedral nanocrystals of CsPbBr3 are explored for facet-selective secondary epitaxial sulfobromide growths. Following a decoupled synthesis process, the heterojunctions are selectively established along {110} as well as {200} facets of 26-faceted rhombicuboctahedrons, the {110} facets of armed hexapods, and the {002} facets of 12-faceted dodecahedron nanocrystals of orthorhombic CsPbBr3. Lattice matching induced these epitaxial growths, and their heterojunctions have been extensively studied with electron microscopic imaging. Unfortunately, these heterostructures did not retain the intense host emission because of their indirect band structures, but such combinations are found to be ideal for promoting photocatalytic CO2 reduction. The pseudo-Type-II combination helped here in the successful movement of charge carriers and also improved the rate of catalysis. These results suggest that facet-selective all-inorganic perovskite heterostructures can be epitaxially grown and this could help in improving their catalytic activities.

Epitaxial Growth of Lead-Free 2D Cs3 Cu2 I5 Perovskites for High-Performance UV Photodetectors.

Abstract: The all-inorganic lead-free Cu-based halide perovskites represented by the Cs-Cu-I system, have sparked extensive interest recently due to their impressive photophysical characteristics. However, successive works on their potential application in light emission diodes and photodetectors rely on tiny polycrystals, in which the grain boundaries and defects may lead to the performance degradation of their embodied devices. Here, 2D all-inorganic perovskite Cs3 Cu2 I5 single crystals are epitaxially grown on mica substrates, with a thickness down to 10 nm. The strong blue emission of the Cs3 Cu2 I5 flakes may originate from the radiative transition of self-trapped excitons associated with a large Stocks shift and long (microsecond) decay time. Ultravioelt (UV) photodetectors based on individual Cs3 Cu2 I5 nanosheets are fabricated via a swift and etching-free dry transfer approach, which reveal a high responsivity of 3.78 A W-1 (270 nm, 5 V bias), as well as a fast response speed (τrise ≈163 ms, τdecay ≈203 ms), outperforming congeneric UV sensors based on other 2D metal halide perovskites. This work therefore sheds light on the fabrication of green optoelectronic devices based on lead-free 2D perovskites, vital for the sustainable development of photoelectric technology.

Epitaxial Growth of Ultrathin Highly-Crystalline Pt-Ni Nanostructure on Metal Carbide Template for Efficient Oxygen Reduction Reaction.

Abstract: Structure engineering strategies such as core-shell and hollow nanostructures are effective pathways to improve the utilization of noble metals for catalysis. However, nowadays materials design based on these strategies are still largely rely on precious metals templates. Herein, we report the epitaxial growth of highly-crystalline Pt3 Ni overlayer on earth abundant nickel carbide, forming Ni3 C@Pt3 Ni core-shell nanoparticles with well-define interface through a new lattice-match-directed synthetic strategy. Derived from such core-shell nanostructure, ultrathin highly-crystalline Pt3 Ni nanocage has an advantageous configuration of ORR favored facets and inherent high active surface area for ORR, bringing high mass activity and specific activity as much as 4.71 A/mgPt and 5.14 mA/cm2 , which are 26 and 20 times to that of commercial Pt/C, respectively. This novel epitaxial growth of platinum opens up new avenues to rationally design highly active and economical electrocatalysts. This article is protected by copyright. All rights reserved.

Epitaxial growth of inch-scale single-crystal transition metal dichalcogenides through the patching of unidirectionally orientated ribbons

Abstract: Two-dimensional (2D) semiconductors, especially transition metal dichalcogenides (TMDs), have been envisioned as promising candidates in extending Moore's law. To achieve this, the controllable growth of wafer-scale TMDs single crystals or periodic single-crystal patterns are fundamental issues. Herein, we present a universal route for synthesizing arrays of unidirectionally orientated monolayer TMDs ribbons (e.g., MoS2, WS2, MoSe2, WSe2, MoSxSe2-x), by using the step edges of high-miller-index Au facets as templates. Density functional theory calculations regarding the growth kinetics of specific edges have been performed to reveal the morphological transition from triangular domains to patterned ribbons. More intriguingly, we find that, the uniformly aligned TMDs ribbons can merge into single-crystal films through a one-dimensional edge epitaxial growth mode. This work hereby puts forward an alternative pathway for the direct synthesis of inch-scale uniform monolayer TMDs single-crystals or patterned ribbons, which should promote their applications as channel materials in high-performance electronics or other fields.

Graphene-driving strain engineering to enable strain-free epitaxy of AlN film for deep ultraviolet light-emitting diode

Abstract: Abstract The energy-efficient deep ultraviolet (DUV) optoelectronic devices suffer from critical issues associated with the poor quality and large strain of nitride material system caused by the inherent mismatch of heteroepitaxy. In this work, we have prepared the strain-free AlN film with low dislocation density (DD) by graphene (Gr)-driving strain-pre-store engineering and a unique mechanism of strain-relaxation in quasi-van der Waals (QvdW) epitaxy is presented. The DD in AlN epilayer with Gr exhibits an anomalous sawtooth-like evolution during the whole epitaxy process. Gr can help to enable the annihilation of the dislocations originated from the interface between AlN and Gr/sapphire by impelling a lateral two-dimensional growth mode. Remarkably, it can induce AlN epilayer to pre-store sufficient tensile strain during the early growth stage and thus compensate the compressive strain caused by hetero-mismatch. Therefore, the low-strain state of the DUV light-emitting diode (DUV-LED) epitaxial structure is realized on the strain-free AlN template with Gr. Furthermore, the DUV-LED with Gr demonstrate 2.1 times enhancement of light output power and a better stability of luminous wavelength compared to that on bare sapphire. An in-depth understanding of this work reveals diverse beneficial impacts of Gr on nitride growth and provides a novel strategy of relaxing the vital requirements of hetero-mismatch in conventional heteroepitaxy.

The Intrinsic Thermodynamic Difficulty and a Step‐Guided Mechanism for the Epitaxial Growth of Uniform Multilayer MoS2 with Controllable Thickness

Abstract: Multilayer MoS2 shows superior performance over the monolayer MoS2 for electronic devices while the growth of multilayer MoS2 with controllable and uniform thickness is still very challenging. It is revealed by calculations that monolayer MoS2 domains are thermodynamically much more favorable than multilayer ones on epitaxial substrates due to the competition between surface interactions and edge formation, leading accordingly to a layer‐by‐layer growth pattern and non‐continuously distributed multilayer domains with uncontrollable thickness uniformity. The thermodynamics model also suggests that multilayer MoS2 domains with aligned edges can significantly reduce their free energy and represent a local minimum with very prominent energy advantage on a potential energy surface. However, the nucleation probability of multilayer MoS2 domains with aligned edges is, if not impossible, extremely rare on flat substrates. Herein, a step‐guided mechanism for the growth of uniform multilayer MoS2 on an epitaxial substrate is theoretically proposed. The steps with proper height on sapphire surface are able to guide the simultaneous nucleation of multilayer MoS2 with aligned edges and uniform thickness, and promote the continuous growth of multilayer MoS2 films. The proposed mechanism can be reasonably extended to grow multilayer 2D materials with uniform thickness on epitaxial substrates.

From Fully Strained to Relaxed: Epitaxial Ferroelectric Al1‐xScxN for III‐N Technology

Abstract: The recent emergence of wurtzite‐type nitride ferroelectrics such as Al1‐xScxN has paved the way for the introduction of all‐epitaxial, all‐wurtzite‐type ferroelectric III‐N semiconductor heterostructures. This paper presents the first in‐depth structural and electrical characterization of such an epitaxial heterostructure by investigating sputter deposited Al1‐xScxN solid solutions with x between 0.19 and 0.28 grown over doped n‐GaN. The results of detailed structural investigations on the strain state and the initial unit‐cell polarity with the peculiarities observed in the ferroelectric response are correlated. Among these, a Sc‐content dependent splitting of the ferroelectric displacement current into separate peaks, which can be correlated with the presence of multiple strain states in the Al1‐xScxN films is discussed. Unlike in previously reported studies on ferroelectric Al1‐xScxN, all films thicker than 30 nm grown on the metal (M)‐polar GaN template feature an initial multidomain state. The results support that regions with opposed polarities in as‐grown films do not result as a direct consequence of the in‐plane strain distribution, but are rather mediated by the competition between M‐polar epitaxial growth on an M‐polar template and a deposition process that favors nitrogen (N)‐polar growth.

Thin‐Film Ferroelectrics

Abstract: Over the last 30 years, the study of ferroelectric oxides has been revolutionized by the implementation of epitaxial‐thin‐film‐based studies, which have driven many advances in the understanding of ferroelectric physics and the realization of novel polar structures and functionalities. New questions have motivated the development of advanced synthesis, characterization, and simulations of epitaxial thin films and, in turn, have provided new insights and applications across the micro‐, meso‐, and macroscopic length scales. This review traces the evolution of ferroelectric thin‐film research through the early days developing understanding of the roles of size and strain on ferroelectrics to the present day, where such understanding is used to create complex hierarchical domain structures, novel polar topologies, and controlled chemical and defect profiles. The extension of epitaxial techniques, coupled with advances in high‐throughput simulations, now stands to accelerate the discovery and study of new ferroelectric materials. Coming hand‐in‐hand with these new materials is new understanding and control of ferroelectric functionalities. Today, researchers are actively working to apply these lessons in a number of applications, including novel memory and logic architectures, as well as a host of energy conversion devices.

Epitaxial growth of inch-scale single-crystal transition metal dichalcogenides through the patching of unidirectionally orientated ribbons

Abstract: Two-dimensional (2D) semiconductors, especially transition metal dichalcogenides (TMDs), have been envisioned as promising candidates in extending Moore's law. To achieve this, the controllable growth of wafer-scale TMDs single crystals or periodic single-crystal patterns are fundamental issues. Herein, we present a universal route for synthesizing arrays of unidirectionally orientated monolayer TMDs ribbons (e.g., MoS2, WS2, MoSe2, WSe2, MoSxSe2-x), by using the step edges of high-miller-index Au facets as templates. Density functional theory calculations regarding the growth kinetics of specific edges have been performed to reveal the morphological transition from triangular domains to patterned ribbons. More intriguingly, we find that, the uniformly aligned TMDs ribbons can merge into single-crystal films through a one-dimensional edge epitaxial growth mode. This work hereby puts forward an alternative pathway for the direct synthesis of inch-scale uniform monolayer TMDs single-crystals or patterned ribbons, which should promote their applications as channel materials in high-performance electronics or other fields.

Epitaxial Grown Sb2Se3@Sb2S3 Core-Shell Nanorod Radial-Axial Hierarchical Heterostructure with Enhanced Photoelectrochemical Water Splitting Performance.

Abstract: Antimony selenide (Sb2Se3) as a light-harvesting material has gradually attracted the attention of researchers in the field of photoelectrocatalysis. Uniquely, the crystal structure consists of one-dimensional (Sb4Se6)n ribbons, with an efficient carrier transport along the ribbon [001] direction. Herein, a novel Sb2Se3@Sb2S3 core-shell nanorod radial-axial hierarchical heterostructure was successfully fabricated by epitaxial growth strategy. Taking advantage of the isomorphous and anisotropic binding modes of (Sb4S(e)6)n ribbons for Sb2Se3 and Sb2S3, the epitaxially grown core-shell heterostructure forms a van der Waals heterojunction across the radial direction and covalently bonded heterojunction along the axial direction. A photocurrent of 1.37 mA cm-2 was achieved at 0 V vs RHE for the hierarchical Sb2Se3@Sb2S3 nanorod photoelectrode with [101] preferred orientation, up to 40 times higher than for pure Sb2Se3. Moreover, the FeOOH was introduced as a cocatalyst. The photoelectrode decorated with FeOOH shows better stability with a H2 generation rate of 18.9 μmol cm-2 h-1 under neutral conditions. This study provides a new insight into the design of antimony chalcogenide heterostructure photoelectrodes for photoelectrochemical water splitting.

Epitaxial growth of an atom-thin layer on a LiNi0.5Mn1.5O4 cathode for stable Li-ion battery cycling

Abstract: Abstract Transition metal dissolution in cathode active material for Li-based batteries is a critical aspect that limits the cycle life of these devices. Although several approaches have been proposed to tackle this issue, this detrimental process is not yet overcome. Here, benefitting from the knowledge developed in the semiconductor research field, we apply an epitaxial method to construct an atomic wetting layer of LaTMO 3 (TM = Ni, Mn) on a LiNi 0.5 Mn 1.5 O 4 cathode material. Experimental measurements and theoretical analyses confirm a Stranski–Krastanov growth, where the strained wetting layer forms under thermodynamic equilibrium, and it is self-limited to monoatomic thickness due to the competition between the surface energy and the elastic energy. Being atomically thin and crystallographically connected to the spinel host lattices, the LaTMO 3 wetting layer offers long-term suppression of the transition metal dissolution from the cathode without impacting its dynamics. As a result, the epitaxially-engineered cathode material enables improved cycling stability (a capacity retention of about 77% after 1000 cycles at 290 mA g −1 ) when tested in combination with a graphitic carbon anode and a LiPF 6 -based non-aqueous electrolyte solution.

Mid-infrared III–V semiconductor lasers epitaxially grown on Si substrates

Abstract: There is currently much activity toward the integration of mid-infrared semiconductor lasers on Si substrates for developing a variety of smart, compact, sensors based on Si-photonics integrated circuits. We review this rapidly-evolving research field, focusing on the epitaxial integration of antimonide lasers, the only technology covering the whole mid-to-far-infrared spectral range. We explain how a dedicated molecular-beam epitaxy strategy allows for achieving high-performance GaSb-based diode lasers, InAs/AlSb quantum cascade lasers, and InAs/GaInSb interband cascade lasers by direct growth on on-axis (001)Si substrates, whereas GaAs-on-Si or GaSb-on-Si layers grown by metal-organic vapor phase epitaxy in large capability epitaxy tools are suitable templates for antimonide laser overgrowth. We also show that etching the facets of antimonide lasers grown on Si is a viable approach in view of photonic integrated circuits. Remarkably, this review shows that while diode lasers are sensitive to residual crystal defects, the quantum cascade and interband cascade lasers grown on Si exhibit performances comparable to those of similar devices grown on their native substrates, due to their particular band structures and radiative recombination channels. Long device lifetimes have been extrapolated for interband cascade lasers. Finally, routes to be further explored are also presented.

Dative Epitaxy of Commensurate Monocrystalline Covalent van der Waals Moiré Supercrystal

Abstract: Realizing van der Waals (vdW) epitaxy in the 1980s represents a breakthrough that circumvents the stringent lattice matching and processing compatibility requirements in conventional covalent heteroepitaxy. However, due to the weak vdW interactions, there is little control over film qualities by the substrate. Typically, discrete domains with a spread of misorientation angles are formed, limiting the applicability of vdW epitaxy. Here, the epitaxial growth of monocrystalline, covalent Cr5Te8 2D crystals on monolayer vdW WSe2 by chemical vapor deposition is reported, driven by interfacial dative bond formation. The lattice of Cr5Te8, with a lateral dimension of a few tens of micrometers, is fully commensurate with that of WSe2 via 3 × 3 (Cr5Te8)/7 × 7 (WSe2) supercell matching, forming a single‐crystalline moiré superlattice. This work establishes a conceptually distinct paradigm of thin‐film epitaxy, termed “dative epitaxy”, which takes full advantage of covalent epitaxy with chemical bonding for fixing the atomic registry and crystal orientation, while circumventing its stringent lattice matching and processing compatibility requirements; conversely, it ensures the full flexibility of vdW epitaxy, while avoiding its poor orientation control. Cr5Te8 2D crystals grown by dative epitaxy exhibit square magnetic hysteresis, suggesting minimized interfacial defects that can serve as pinning sites.

Epitaxial Electrocrystallization of Magnesium via Synergy of Magnesiophilic Interface, Lattice Matching, and Electrostatic Confinement.

Abstract: Rechargeable magnesium batteries are particularly advantageous for renewable energy storage systems. However, the inhomogeneous Mg electrodeposits greatly shorten their cycle life under practical conditions. Herein, the epitaxial electrocrystallization of Mg on a three-dimensional magnesiophilic host is implemented via the synergy of a magnesiophilic interface, lattice matching, and electrostatic confinement effects. The vertically aligned nickel hydroxide nanosheet arrays grown on carbon cloth (abbreviated as "Ni(OH)2@CC") have been delicately designed, which satisfy the essential prerequisite of a low lattice geometrical misfit with Mg (about 2.8%) to realize epitaxial electrocrystallization. Simultaneously, the ionic crystal nature of Ni(OH)2 displays a periodic and hillock-like electrostatic potential field over its exposed facets, which can precisely capture and confine the reduced Mg0 species onto the local electron-enriched sites at the atomic level. The Ni(OH)2@CC substrate undergoes sequential Mg-ion intercalation, underpotential deposition, and electrocrystallization processes, during which the uniform, lamellar Mg electrodeposits with a locked crystallographic orientation are formed. Under practical conditions (10 mA cm-2 and 10 mAh cm-2), the Ni(OH)2@CC substrate exhibits stable Mg stripping/plating cycle performances over 600 h, 2 orders of magnitude longer than those of the pristine copper foil and carbon cloth substrates.