Atomic Layer Deposition of WO3-Doped In2O3 for Reliable and Scalable BEOL-Compatible Transistors.

Tungsten oxide (WO3) doped indium oxide (IWO) field-effect transistors (FET), synthesized using atomic layer deposition (ALD) for three-dimensional integration and back-end-of-line (BEOL) compatibility, are demonstrated. Low-concentration (1∼4 W atom %) WO3-doping in In2O3 films is achieved by adjusting cycle ratios of the indium and tungsten precursors with the oxidant coreactant. Such doping suppresses oxygen deficiency from In2O2.5 to In2O3 stoichiometry with only 1 atom % W, allowing devices to turn off stably and enhancing threshold voltage stability. The ALD IWO FETs exhibit superior performance, including a low subthreshold slope of 67 mV/decade and negligible hysteresis. Strong tunability of the threshold voltage (Vth) is achieved through W concentration tuning, with 2 atom % IWO FETs showing an optimized Vth for enhancement-mode and a high drain current. ALD IWO FETs have remarkable stability under bias stress and nearly ideal performance extending to sub-100 nm channel lengths, making them promising candidates for high-performance monolithic 3D integrated devices.

Understanding Trap States in InP and GaP Quantum Dots through Density Functional Theory.

The widespread application of III-V colloidal quantum dots (QDs) as nontoxic, highly tunable emitters is stymied by their high density of trap states. Here, we utilize density functional theory (DFT) to investigate trap state formation in a diverse set of realistically passivated core-only InP and GaP QDs. Through orbital localization techniques, we deconvolute the dense manifold of trap states to allow for detailed assignment of surface defects. We find that the three-coordinate species dominate trapping in III-V QDs and identify features in the geometry and charge environment of trap centers capable of deepening, or sometimes passivating, traps. Furthermore, we observe stark differences in surface reconstruction between InP and GaP, where the more labile InP reconstructs to passivate three-coordinate indium at the cost of distortion elsewhere. These results offer explanations for experimentally observed trapping behavior and suggest new avenues for controlling trap states in III-V QDs.

Strong Linearly Polarized Light Emission by Coupling Out-of-Plane Exciton to Anisotropic Gap Plasmon Nanocavity.

With exceptional quantum confinement, 2D monolayer semiconductors support a strong excitonic effect, making them an ideal platform for exploring light-matter interactions and as building blocks for novel optoelectronic devices. Different from the well-known in-plane excitons in transition metal dichalcogenides (TMD), the out-of-plane excitons in indium selenide (InSe) usually show weak emission, which limits their applications as light sources. Here, by embedding InSe in an anisotropic gap plasmon nanocavity, we have realized plasmon-enhanced linearly polarized photoluminescence with an anisotropic ratio up to ∼140, corresponding to degree of polarization (DoP) of ∼98.6%. Such polarization selectivity, originating from the polarization-dependent plasmonic enhancement supported by the "nanowire-on-mirror" nanocavity, can be well tuned by the InSe thickness. Moreover, we have also realized an InSe-based light-emitting diode with polarized electroluminescence. Our research highlights the role of excitonic dipole orientation in designing nanophotonic devices and paves the way for developing InSe-based optoelectronic devices with polarization control.

c-Axis Aligned 3 nm Thick In2O3 Crystal Using New Liquid DBADMIn Precursor for Highly Scaled FET Beyond the Mobility-Stability Trade-off.

Oxide semiconductors (OS) are attractive materials for memory and logic device applications owing to their low off-current, high field effect mobility, and superior large-area uniformity. Recently, successful research has reported the high field-effect mobility (µFE) of crystalline OS channel transistors (above 50 cm2 V-1 s-1). However, the memory and logic device application presents challenges in mobility and stability trade-offs. Here, we propose a method for achieving high-mobility and high-stability by lowering the grain boundary effect. A DBADMIn precursor was synthesized to deposit highly c-axis-aligned C(222) crystalline 3 nm thick In2O3 films. In this study, the 250 °C deposited 3 nm thick In2O3 channel transistor exhibited high µFE of 41.12 cm2 V-1 s-1, Vth of -0.50 V, and SS of 150 mV decade-1 with superior stability of 0.16 V positive shift during PBTS at 100 °C, 3 MV cm-1 stress conditions for 3 h.

Interaction of gallium, indium, and vanadyl curcumin complexes with hen egg-white lysozyme (HEWL): Mechanistic aspects and evaluation of antiamyloidogenic activity.

Many proteins and peptides can aggregate into amyloid fibrils with high-ordered and cross-ß rich structure characteristics. Amyloid deposition is a common feature of neurodegenerative diseases called amyloidosis. Various natural polyphenolic compounds such as curcumin exhibited antiamyloidogenic activities, but less researches were focused on the metal complexes of these compounds. In this study, the inhibitory effects of gallium curcumin (Ga(cur)3), indium curcumin (In(cur)3), and vanadyl curcumin (VO(cur)2) on the amyloid fibrillation of hen egg white lysozyme (HEWL) have been investigated. Moreover, the details of binding interactions of these metal complexes with HEWL have been explored. The results of fluorescence quenching analyses revealed that In(cur)3 and VO(cur)2 have much higher binding affinities than Ga(cur)3 toward HEWL. The interactions of these metal complexes were accompanied by partial conformational changes in the tertiary structure of HEWL. The kinetic curves of the fibrillation process demonstrated that In(cur)3 and VO(cur)2 have higher inhibitory effects than Ga(cur)3 on the amyloid fibrillation of HEWL. The strength of binding to HEWL is completely in accordance with inhibitory activities of these metal complexes of curcumin.

Design of a Single-Atom In-N3-S site to Modulate Exciton Behavior in Carbon Nitride for Enhanced Photocatalytic Performance.

Rational tailoring of the local coordination environment of single atoms has demonstrated a significant impact on the electronic state and catalytic performance, but the development of catalysts beyond noble/transition metals is profoundly significant and highly desired. Herein, the main-group metal indium (In) single atom is immobilized on sulfur-doped porous carbon nitride nanosheets (In@CNS) in the form of three nitrogen atoms coordinated with one sulfur atom (In-N3-S). Both theoretical calculations and advanced characterization investigations clearly elucidated that the single-atomic In-N3-S structures on In@CNS are powerful in promoting the dissociation of excitons into more free carriers as well as the charge separation, synergistically elevating electron concentration by 2.19 times with respect to pristine CNS. Meanwhile, the loading of In single atoms on CNS is responsible for altering electronic structure and lowering the Gibbs free energy for hydrogen adsorption. Consequently, the optimized In@CNS-5.0 exhibited remarkable photocatalytic performance, remarkable water-splitting and tetracycline hydrochloride degradation. The H2 production achieved to 10.11 mmol h-1g-1 with a notable apparent quantum yield of 19.70% at 400 nm and remained at 10.40% at 420 nm. These findings open a new perspective for in-depth comprehending the effect of the main-group metal single-atom coordination environment on promoting photocatalytic performance.

The Remarkable Role of Indium in Synergistically Optimizing Carrier Concentration and Phase Distribution of AgCuTe-Based Materials.

Carrier regulation has proven to be an effective approach for optimizing the thermoelectric performance of materials. One common method to adjust the carrier concentration is through element doping. In the case of AgCuTe-based materials, it tends to form with cation vacancies, resulting in a high hole concentration and complex phase composition at low temperatures, which also hinders material stability. However, this also offers additional opportunities to manipulate the carrier concentration. In this study, the improved performance of AgCuTe through indium doping is reported, which leads to a reduction in hole concentration. In combination with a significant increase in the effective mass of the carriers, the enhanced Seebeck coefficient is also realized. Particularly, a notable improvement in power factor is observed in the hexagonal phase near room temperature. Furthermore, a lower electron thermal conductivity is achieved, contributing to an average figure of merit value of ≈1.21 (between 523 and 723 K). Additionally, the presence of indium inhibits the formation of the second phase and ensures a homogeneous phase distribution, which reduces the instability arising from phase transition. This work significantly enhances the potential of AgCuTe-based materials for low to medium-temperature applications.

Engineering Oxygen Vacancies in In2O3 with Enhanced Polysulfides Immobilization and Selective Catalytic Capability.

Lithium-sulfur (Li-S) battery is identified as an ideal candidate for next-generation energy storage systems in consideration of its high theoretical energy density and abundant sulfur resources. However, the shuttling behavior of soluble polysulfides (LiPSs) and their sluggish reaction kinetics severely limit the practical application of the current Li-S battery. In this work, a series of In2O3 nanocubes with different oxygen vacancy concentrations are designed and prepared via a facile self-template method. The introduced oxygen vacancy on In2O3 can effectively rearrange the charge distribution and enhance sulfiphilic property. Moreover, the In2O3 with high oxygen vacancy concentration (H-In2O3) can slightly slow down the solid-liquid conversion process and significantly accelerate the liquid-solid conversion process, thus reducing the accumulation of LiPSs in electrolyte and inhibiting the shuttle effect. Contributed by the unique selective catalytic capability, the prepared H-In2O3 exhibits excellent electrochemical performance when used as sulfur host. For instance, a high reversible capacity of 609 mAh g-1 is obtained with only 0.044% capacity decay per cycle over 1000 cycles at 1.0 C. This work presents a typical example for designing advanced sulfur hosts, which is crucial for the commercialization of Li-S battery.

Water-Soluble Alumina-Coated Indium Phosphide Core-Shell Quantum Dots with Efficient Deep-Red Emission Beyond 700 nm.

Solution-processed colloidal III-V semiconductor-based quantum dots (QDs) represent promising and environmentally-friendly alternatives to Cd-based QDs in the realms of optoelectronics and biological applications. While InP-based core-shell QDs have demonstrated efficient light-emitting diode (LED) performance in the visible region, achieving deep-red emission (above 700 nm) with a narrow linewidth has proven challenging. Herein, the study presents a novel strategy for synthesizing InP/ZnSe/ZnS core-shell-shell QDs tailored for emission in the first biological transparency window. The resulting QDs exhibit an emission wavelength up to 725 nm with a narrow peak full width at half maximum (FWHM) down to 107 meV (45 nm). To enhance the biocompatibility and chemical stability of the QDs, their surface is further capped with a layer of amorphous alumina resulting in an InP/ZnSe/ZnS/Al2O3 heterostructure. This surface passivation not only ensures environmental- and photostability but also enhances the photoluminescence quantum yield (PLQY). The alumina capping enables the aqueous phase transfer via surface ligand exchange using mercaptopropionic acid (MPA) while maintaining the initial quantum yield. The resulting QDs demonstrate a significant potential for advancing next-generation optoelectronic technologies and bio-applications.

Advancements and Challenges in the Integration of Indium Arsenide and Van der Waals Heterostructures.

The strategic integration of low-dimensional InAs-based materials and emerging van der Waals systems is advancing in various scientific fields, including electronics, optics, and magnetics. With their unique properties, these InAs-based van der Waals materials and devices promise further miniaturization of semiconductor devices in line with Moore's Law. However, progress in this area lags behind other 2D materials like graphene and boron nitride. Challenges include synthesizing pure crystalline phase InAs nanostructures and single-atomic-layer 2D InAs films, both vital for advanced van der Waals heterostructures. Also, diverse surface state effects on InAs-based van der Waals devices complicate their performance evaluation. This review discusses the experimental advances in the van der Waals epitaxy of InAs-based materials and the working principles of InAs-based van der Waals devices. Theoretical achievements in understanding and guiding the design of InAs-based van der Waals systems are highlighted. Focusing on advancing novel selective area growth and remote epitaxy, exploring multi-functional applications, and incorporating deep learning into first-principles calculations are proposed. These initiatives aim to overcome existing bottlenecks and accelerate transformative advancements in integrating InAs and van der Waals heterostructures.

General Synthesis of Metal Indium Sulfide Atomic Layers for Photocatalysis.

The metal indium sulfides have attracted extensive research interest in photocatalysis due to regulable atomic configuration and excellent optoelectronic properties. However, the synthesis of metal indium sulfide atomic layers is still challenging since intrinsic non-van-der-Waals layered structures of some components. Here, a surfactant self-assembly growth mechanism is proposed to controllably synthesize metal indium sulfide atomic layers. Eleven types of atomic layers with tunable compositions, thickness, and defect concentrations are successfully achieved namely In2S3, MgIn2S4, CaIn2S4, MnIn2S4, FeIn2S4, ZnIn2S4, Zn2In2S5, Zn4In16S33, CuInS2, CuIn5S8, and CdIn2S4. The typical CaIn2S4 shows a defect-dependence activity for CO2 photoreduction. The designed S vacancies in CaIn2S4 can serve as catalytic centers to activate CO2 molecules via localized electrons for π-back-donation. The engineered S vacancies tune the non-covalent interaction with CO2 and intermediates, manages to tune the free energy, and lower the reaction energy barrier. As a result, the defect-rich CaIn2S4 displays 2.82× improved reduction rate than defect-poor CaIn2S4. Meantime, other components also display promising photocatalytic performance, such as Zn2In2S5 with a H2O2 photosynthesis rate of 292 µmol g-1 h-1 and CuInS2 with N2-NH4 + conversion rate of 54 µmol g-1 h-1. This work paves the way for the multidisciplinary exploration of metal indium sulfide atomic layers with unique photocatalysis properties.

The Growth and Shape Evolution of Indium Nanoplates Studied by In Situ Liquid Cell TEM.

Understanding the growth mechanisms of nanomaterials is crucial for effectively controlling their morphology which may affect their properties. Here, the growth process of indium nanoplates is studied using in situ liquid cell transmission electron microscopy. Quantitative analysis shows that the growth of indium nanoplate is limited by surface reaction. Besides, the growth process has two stages, which is different from that of other metal nanoplates reported previously. At the first stage, indium particles transform gradually from face-centered cubic to body-centered tetragonal (bct) structure as the seeds grow. At the second stage, the seeds grow faster than at the first stage and form indium triangular nanoplates. Indium triangular nanoplates have a bct structure with {011}-twin, which is found to form through kinetic reactions. In addition, the shape evolution of truncated triangle nanoplate with multiple twin planes is studied. The growth rate of truncated edge changes with the varied number of re-entrant grooves. The present work provides valuable insights into the growth mechanism of metal nanoplates with low-symmetric structure and the role of twin planes in the shape evolution of plate-like metal nanomaterials.

Versatile Patterning of Liquid Metal via Multiphase 3D Printing.

This paper presents a scalable and straightforward technique for the immediate patterning of liquid metal/polymer composites via multiphase 3D printing. Capitalizing on the polymer's capacity to confine liquid metal (LM) into diverse patterns. The interplay between distinctive fluidic properties of liquid metal and its self-passivating oxide layer within an oxidative environment ensures a resilient interface with the polymer matrix. This study introduces an inventive approach for achieving versatile patterns in eutectic gallium indium (EGaIn), a gallium alloy. The efficacy of pattern formation hinges on nozzle's design and internal geometry, which govern multiphase interaction. The interplay between EGaIn and polymer within the nozzle channels, regulated by variables such as traverse speed and material flow pressure, leads to periodic patterns. These patterns, when encapsulated within a dielectric polymer polyvinyl alcohol (PVA), exhibit an augmented inherent capacitance in capacitor assemblies. This discovery not only unveils the potential for cost-effective and highly sensitive capacitive pressure sensors but also underscores prospective applications of these novel patterns in precise motion detection, including heart rate monitoring, and comprehensive analysis of gait profiles. The amalgamation of advanced materials and intricate patterning techniques presents a transformative prospect in the domains of wearable sensing and comprehensive human motion analysis.

CuO (111) Microcrystalline Evoked Indium-Organic Framework for Efficient Electroreduction of CO2 to Formate.

Electrochemical reduction of carbon dioxide (CO2RR) to formate is economically beneficial but suffers from poor selectivity and high overpotential. Herein, enriched microcrystalline copper oxide is introduced on the surface of indium-based metal-organic frameworks. Benefiting from the CuO (111) microcrystalline shell and formed catalytic active In-Cu interfaces, the obtained MIL-68(In)/CuO heterostructure display excellent CO2RR to formate with a Faradaic efficiency (FE) as high as 89.7% at low potential of only -0.7 V vs. RHE in a flow cell. Significantly, the membrane electrode assembly (MEA) cell based on MIL-68(In)/CuO exhibit a remarkable current density of 640.3 mA cm-2 at 3.1 V and can be stably operated for 180 h at 2.7 V with a current density of 200 mA cm-2. The ex/in situ electrochemical investigations reveal that the introduction of CuO increases the formation rate of the carbon dioxide reduction intermediate *HCOO- and inhibits the competitive hydrogen evolution reaction. This work not only provides an in-depth study of the mechanism of the CO2RR pathways on In/Cu composite catalyst but also offers an effective strategy for the interface design of electrocatalytic carbon dioxide reduction reaction.

Thermocatalytic Hydrogen Production from Water at Boiling Condition.

Thermochemical water-splitting cycles are technically feasible for hydrogen production from water. However, the ultrahigh operation temperature and low efficiency seriously restrict their practical application. Herein, one-step and one-pot thermocatalytic water-splitting process is reported at water boiling condition catalyzed by single atomic Pt on defective In2O3. Water splitting into hydrogen is verified by D2O isotopic experiment, with an optimized hydrogen production rate of 36.4 mmol·h-1·g-1 as calculated on Pt active sites. It is revealed that three-centered Pt1In2 surrounding oxygen vacancy as catalytic ensembles promote the dissociation of the adsorbed water into H, which transfers to singlet atomic Pt sites for H2 production. Remaining OH groups on adjacent In sites from Pt1In2 ensembles undergoes O─O bonding, hyperoxide formation and diminishing via triethylamine oxidation, water re-adsorption for completing the catalytic cycle. Current work represents an isothermal and continuous thermocatalytic water splitting under mild condition, which can re-awaken the research interest to produce H2 from water using low-grade heat and competes with photocatalytic, electrolytic, and photoelectric reactions.

Regulation Strategy of Nanostructured Engineering on Indium-Based Materials for Electrocatalytic Conversion of CO2.

Electrochemical carbon dioxide reduction (CO2 RR), as an emerging technology, can combine with sustainable energies to convert CO2 into high value-added products, providing an effective pathway to realize carbon neutrality. However, the high activation energy of CO2 , low mass transfer, and competitive hydrogen evolution reaction (HER) leads to the unsatisfied catalytic activity. Recently, Indium (In)-based materials have attracted significant attention in CO2 RR and a series of regulation strategies of nanostructured engineering are exploited to rationally design various advanced In-based electrocatalysts, which forces the necessary of a comprehensive and fundamental summary, but there is still a scarcity. Herein, this review provides a systematic discussion of the nanostructure engineering of In-based materials for the efficient electrocatalytic conversion of CO2 to fuels. These efficient regulation strategies including morphology, size, composition, defects, surface modification, interfacial structure, alloying, and single-atom structure, are summarized for exploring the internal relationship between the CO2 RR performance and the physicochemical properties of In-based catalysts. The correlation of electronic structure and adsorption behavior of reaction intermediates are highlighted to gain in-depth understanding of catalytic reaction kinetics for CO2 RR. Moreover, the challenges and opportunities of In-based materials are proposed, which is expected to inspire the development of other effective catalysts for CO2 RR.

Novel Polytype of III-VI Metal Chalcogenides Nano Crystals Realized in Epitaxially Grown InTe.

III-VI metal chalcogenides have garnered considerable research attention as a novel group of layered van der Waals materials because of their exceptional physical properties and potential technological applications. Here, the epitaxial growth and stacking sequences of InTe is reported, an essential and intriguing material from III-VI metal chalcogenides. Aberration-corrected scanning transmission electron microscopy (STEM) is utilized to directly reveal the interlayer stacking modes and atomic structure, leading to a discussion of a new polytype. Furthermore, correlations between the stacking sequences and interlayer distances are substantiated by atomic-resolution STEM analysis, which offers evidence for strong interlayer coupling of the new polytype. It is proposed that layer-by-layer deposition is responsible for the formation of the unconventional stacking order, which is supported by ab initio density functional theory calculations. The results thus establish molecular beam epitaxy as a viable approach for synthesizing novel polytypes. The experimental validation of the InTe polytype here expands the family of materials in the III-VI metal chalcogenides while suggesting the possibility of new stacking sequences for known materials in this system.

Indium(III) complexes with lapachol: cytotoxic effects against human breast tumor cells and interactions with DNA.

Lapachol (2-hydroxy-3-(3-methylbut-2-en-1-yl)naphthalene-1,4-dione) is a 1,4-naphthoquinone-derived natural product that presents numerous bioactivities and was shown to have cytotoxic effects against several human tumor cells. Indium(III) complexes with a variety of ligands also exhibit antineoplastic activity. Indium(III) complexes [In(lap)Cl2].4H2O (1), [In(lap)2Cl(Et3N)] (2), [In(lap)3]·2H2O (3) [In(lap)(bipy)Cl2] bipy = 2,2'-bipyridine (4) and [In(lap)(phen)Cl2] phen = 1,10-phenanthroline (5) were obtained with 2-hydroxy-3-(3-methylbut-2-en-1-yl)naphthalene-1,4-dione (lapachol). Crystal structure determinations for (4) and (5) revealed that the indium(III) center is coordinated to two O atoms from lapachol, two N atoms from 1,10-phenanthroline or 2,2'-bipyridine, and two chloride anions, in a distorted octahedral geometry. Although both complexes (4) and (5) interacted with CT-DNA in vitro by an intercalative mode, only 5 exhibited cytotoxicity against MCF-7 and MDA-MB breast tumor cells. 1,10-phenanthroline and complex (5) presented cytotoxic effects against MCF-7 and MDA-MB cells, with complex (5) being threefold more active than 1,10-phenanthroline on MCF-7 cells. In addition, complex (5) significantly reduced the formation of MDA-MB-231 colonies in a clonogenicity assay. The foregoing results suggest that further studies on the cytotoxic effects and cellular targets of complex (5) are of utmost relevance.

Reactivity of a Neutral Yttrium(III) Trimethyl Complex toward Brønsted and Lewis Acids.

The present study corroborates that the neutral tridentate N-ligand 1,4,7-trimethyl-triazacyclononane (Me3TACN) qualifies as a versatile platform to study selective ligand exchange with rare-earth-metal alkyl complexes, herein [(Me3TACN)YMe3]. Treatment with Brønsted-acidic bis(dimethylsilyl)amine, HN(SiHMe2)2, gave selectively the mono-exchanged heteroleptic complex [(Me3TACN)YMe2{N(SiHMe2)2}]. Depending on the molecular ratio employed, the reaction of [(Me3TACN)YMe3] with AlMe3 resulted in the isolation/crystallization of [(Me3TACN)YMe2(AlMe4)] [1 : 1] or ion-separated [(Me3TACN)YMe(AlMe4)][AlMe4] [1 : 2] and [(Me3TACN)YMe(AlMe4)][Al2Me7] [1 : 3]. Analogous reactions with the heavier group 13 methyls GaMe3 and InMe3 generated mixed methyl/tetramethylgallato complex [(Me3TACN)YMe2(GaMe4)] and ion-separated [{(Me3TACN)YMe2}2{µ-Me}][InMe4]. Finally, dimethylalane, HAlMe2, converted [(Me3TACN)YMe3] into heteroaluminate [(Me3TACN)Y(HAlMe3)3], representing an AlMe3-supported, molecular yttrium trihydride complex. All compounds were investigated by single crystal X-ray diffraction (SC-XRD), homo- and heteronuclear (13C, 27Al, 89Y, 115In) NMR as well as IR spectroscopies and elemental analyses.

Direct Band Gap Semiconductors with Two- and Three-Dimensional Triel-Phosphide Frameworks (Triel=Al, Ga, In).

Recently, several ternary phosphidotrielates and -tetrelates have been investigated with respect to their very good ionic conductivity, while less focus was pointed towards their electronic structures. Here, we report on a novel series of compounds, in which several members possess direct band gaps. We investigated the known compounds Li3AlP2, Li3GaP2, Li3InP2, and Na3InP2 and describe the synthesis and the crystal structure of novel Na3In2P3. For all mentioned phosphidotrielates reflectance UV-Vis measurements reveal direct band gaps in the visible light region with decreasing band gaps in the series: Li3AlP2 (2.45 eV), Li3GaP2 (2.18 eV), Li3InP2 (1.99 eV), Na3InP2 (1.37 eV), and Na3In2P3 (1.27 eV). All direct band gaps are confirmed by quantum chemical calculations. The unexpected property occurs despite different structure types. As a common feature all compounds contain EP4 tetrahedra, which share exclusively vertices for E=In and vertices as well as edges for E=Al and Ga. The structure of the novel Na3In2P3 is built up by a polyanionic framework of six-membered rings of corner-sharing InP4 tetrahedra. As a result, the newly designed semiconductors with direct band gaps are suitable for optoelectronic applications, and they can provide significant guidance for the design of new functional semiconductors.