Atomic Layer Deposition Process Research Articles

Preparation of palladium-based catalyst by plasma-assisted atomic layer deposition and its applications in CO2 hydrogenation reduction

Supported Pd catalyst is an important noble metal material in recent years due to its high catalytic performance in CO2 hydrogenation. A fluidized-bed plasma assisted atomic layer deposition (FP-ALD) process is reported to fabricate Pd nanoparticle catalyst over γ-Al2O3 or Fe2O3/γ-Al2O3 support, using palladium hexafluoroacetylacetonate as the Pd precursor and H2 plasma as counter-reactant. Scanning transmission electron microscopy exhibits that high-density Pd nanoparticles are uniformly dispersed over Fe2O3/γ-Al2O3 support with an average diameter of 4.4 nm. The deposited Pd-Fe2O3/γ-Al2O3 shows excellent catalytic performance for CO2 hydrogenation in a dielectric barrier discharge reactor. Under a typical condition of H2 to CO2 ratio of 4 in the feed gas, the discharge power of 19.6 W, and gas hourly space velocity of 10000 h−1, the conversion of CO2 is as high as 16.3% with CH3OH and CH4 selectivities of 26.5% and 3.9%, respectively.

Enhancing Carbon Fiber Fabrics with ALD AlxOy Coatings: An Investigation of Thickness Effects on Weight, Morphology, Coloration, and Thermal Properties

This study explores the impact of non-stoichiometric aluminum oxide (AlxOy) coatings applied via thermal atomic layer deposition (ALD) on carbon fiber fabrics (CFFs), emphasizing volume per cycle, FESEM analyses, color transitions, and thermal stability enhancements. Using trimethylaluminum and water at 100 °C, AlxOy was deposited across a range of 1000 to 5000 ALD cycles, with film thicknesses extending up to 500 nm. This notable increase in the volume of material deposited per cycle was observed for the 3D CFFs, highlighting ALD’s capability to coat complex structures effectively. FESEM analyses revealed the morphological evolution of CFF surfaces post-coating, showing a transition from individual grains to a dense, continuous layer as ALD cycles increased. This morphological transformation led to significant color shifts from green to red to blue, attributed to structural coloration effects arising from variations in film thickness and surface morphology. Thermogravimetric analyses (TGA and dTG) indicated that the AlxOy coatings enhanced the thermal stability of CFFs, with a postponement in degradation onset observed in samples subjected to more ALD cycles. In essence, this research highlights the nuanced relationship between ALD processing parameters and their collective influence on both the aesthetic and functional properties of CFFs. This study illustrates ALD’s potential in customizing CFFs for applications requiring specific color and thermal resilience, balancing the discussion between the surface morphological changes and their implications for color and thermal behavior.

Exploring TMA and H2O Flow Rate Effects on Al2O3 Thin Film Deposition by Thermal ALD: Insights from Zero-Dimensional Modeling

This study investigates the impact of vapour-phase precursor flow rates—specifically those of trimethylaluminum (TMA) and deionized water (H2O)—on the deposition of aluminum oxide (Al2O3) thin films through atomic layer deposition (ALD). It explores how these flow rates influence film growth kinetics and surface reactions, which are critical components of the ALD process. The research combines experimental techniques with a zero-dimensional theoretical model, designed specifically to simulate the deposition dynamics. This model integrates factors such as surface reactions and gas partial pressures within the ALD chamber. Experimentally, Al2O3 films were deposited at varied TMA and H2O flow rates, with system conductance guiding these rates across different temperature settings. Film properties were rigorously assessed using optical reflectance methods and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy. The experimental findings revealed a pronounced correlation between precursor flow rates and film growth. Specifically, at 150 °C, film thickness reached saturation at a TMA flow rate of 60 sccm, while at 200 °C, thickness peaked and then declined with increasing TMA flow above this rate. Notably, higher temperatures generally resulted in thinner films due to increased desorption rates, whereas higher water flow rates consistently produced thicker films, emphasizing the critical role of water vapour in facilitating surface reactions. This integrative approach not only deepens the understanding of deposition mechanics, particularly highlighting how variations in precursor flow rates distinctly affect the process, but also significantly advances operational parameters for ALD. These insights are invaluable for enhancing the application of ALD technologies across diverse sectors, including microelectronics, photovoltaics, and biomedical coatings, effectively bridging the gap between theoretical predictions and empirical results.

Bilateral Production Shield Enabling Highly Efficient Perovskite Photovoltaics.

Enhancing the intrinsic stability of perovskite and through encapsulation to isolate water, oxygen, and UV-induced decomposition are currently common and most effective strategies in perovskite solar cells. Here, the atomic layer deposition process is employed to deposit a nanoscale (≈100nm), uniform, and dense Al2O3 film on the front side of perovskite devices, effectively isolating them from the erosion caused by water and oxygen in the humid air. Simultaneously, nanoscale (≈100nm) TiO2 films are also deposited on the glass surface to efficiently filter out the ultraviolet (UV) light in the light source, which induces degradation in perovskite. Ultimately, throughthe collaborative effects of both aspects, the stability of the devices is significantly improved under conditions of humid air and illumination. As a result, after storing the devices in ambient air for 1000h, the efficiency only declines to 95%, and even after 662h of UV exposure, the efficiency remains at 88%, far surpassing the performance of comparison devices. These results strongly indicate that the adopted Al2O3 and TiO2 thin films play a significant role in enhancing the stability of perovskite solar cells, demonstrating substantial potential for widespread industrial applications.

Tailoring indium oxide film characteristics through oxygen reactants in atomic layer deposition with highly reactive liquid precursor

Indium oxide (InOx) films were deposited via atomic layer deposition (ALD) using a novel liquid indium precursor, dimethyl[N1-(tert-butyl)–N2,N2-dimethylethane-1,2-diamine]indium (DMITN). In this process, the reactant (H2O, O3, or O2 plasma) and substrate temperature (100–250 ℃) were varied. The DMITN precursor showed excellent reactivity with all three reactants. The growth characteristics (ALD window, growth per cycle, and step coverage) and film properties (impurities, stoichiometry, oxygen bonding state, crystallinity, film density, and electrical properties) differed based on the ALD process employed, ascribed to the distinct thermal energies and inherent reactivities of the chosen oxidants. As the oxidation energy of the reactants increased (H2O < O3 < O2 plasma), the growth per cycle (GPC) and the oxygen–indium bond ratio of InOx increased. Crystallinity analysis also revealed significant differences depending on the reactants, where the Hall mobility was predominantly influenced by the crystal alignment. The step coverage at an aspect ratio of 40:1 was markedly superior with the use of H2O and O3 reactants (approximately 95 %) compared to that with O2 plasma (approximately 74 %). These findings highlight the capability of controlling the growth and properties of InOx films by judiciously selecting the reactant, emphasizing the versatility of the DMITN precursor in ALD processes.

Simultaneous Band Alignment Modulation and Carrier Dynamics Optimization Enable Highest Efficiency in Cd‐Free Sb2Se3 Solar Cells

AbstractAntimony selenide (Sb2Se3) has developed as an eco‐friendly photovoltaic candidate owing to its non‐toxic composition and exceptional optoelectronic properties. However, the toxic and parasitic light‐absorbing CdS are widely used as electron transport layer (ETL) in Sb2Se3 solar cells, which severely limits its development. Herein, an alternative, zinc tin oxide (ZTO) ETL with varying composition‐dependent energy structure is deposited by atomic layer deposition (ALD) technique and used for constructing Cd‐free Sb2Se3 solar cells. It has been found that the ZTO ETL possessing an appropriate Zn/Sn ratio can alter the Sb2Se3/ZTO heterojunction band alignment to an ideal “spike‐like” arrangement. It not only suppresses the accumulation and recombination of charge carriers at the interface, but also effectively enhances carrier transport. In addition, thanks to the formation of passivated Sb2O3 ultra‐thin layer upon ALD process, the non‐radiative recombination within bulk Sb2Se3 can be effectively suppressed, and therefore enhancing carrier lifetime, extraction efficiency, and collection efficiency. Consequently, the as‐fabricated Mo/Sb2Se3/ZTO/ITO/Ag thin‐film solar cell demonstrates an impressive efficiency of 8.63%. This accomplishment establishes it as the most efficient Cd‐free Sb2Se3 solar cell to date, underscoring the significant advantages of incorporating ZTO ETL in the development of Sb2Se3 photovoltaic scenarios.

Generation and Applications of a Broad Atomic Oxygen Beam with a High Flux‐Density via Collision‐Induced Dissociation of O2

Generation and Applications of a Broad Atomic Oxygen Beam with a High <scp>Flux‐Density</scp> via <scp>Collision‐Induced</scp> Dissociation of <scp>O₂</scp>

Targeting Manganese Amidinates and ß-Ketoiminates Complexes as Precursors for Mn-Based Thin Film Vapor Deposition.

With a focus on Mn based organometallic compounds with suitable physico-chemical properties to serve as precursors for chemical vapor deposition (CVD) and atomic layer deposition (ALD) of Mn-containing materials, systematic synthetic approaches with ligand variation, detailed characterization, and theoretical input from density functional theory (DFT) studies are presented. A series of new homoleptic all-nitrogen and mixed oxygen/nitrogen-coordinated Mn(II) complexes bearing the acetamidinate, formamidinate, guanidinate and ß-ketoiminate ligands have been successfully synthesized for the first time. The specific choice of these ligand classes with changes in structure and coordination sphere and side chain variations result in significant structural differences whereby mononuclear and dinuclear complexes are formed. This was supported by density functional theory (DFT) studies. The compounds were thoroughly characterized by single crystal X-ray diffraction, magnetic measurements, mass spectrometry and elemental analysis. To evaluate their suitability as precursors for deposition of Mn-based materials, the thermal properties were investigated in detail. Mn(II) complexes possessing the most promising thermal properties, namely Bis(N,N´-ditertbutylformamidinato)manganese(II) (IV) and Bis(4-(isopropylamino)pent-3-en-2-onato)manganese(II) (ßIII) were used in reactivity studies with DFT to explore their interaction with oxidizing co-reactants such as oxygen and water which will guide future CVD and ALD process development.

Plasma enhanced atomic layer deposition of silicon nitride using magnetized very high frequency plasma

To obtain high-quality SiN x films applicable to an extensive range of processes, such as gate spacers in fin field-effect transistors (FinFETs), the self-aligned quadruple patterning process, etc, a study of plasma with higher plasma density and lower plasma damage is crucial in addition to study on novel precursors for SiN x plasma-enhanced atomic layer deposition (PEALD) processes. In this study, a novel magnetized PEALD process was developed for depositing high-quality SiN x films using di(isopropylamino)silane (DIPAS) and magnetized N2 plasma at a low substrate temperature of 200 °C. The properties of the deposited SiN x films were analyzed and compared with those obtained by the PEALD process using a non-magnetized N2 plasma source under the same conditions. The PEALD SiN x film, produced using an external magnetic field (ranging from 0 to 100 G) during the plasma exposure step, exhibited a higher growth rate (∼1 Å/cycle) due to the increased plasma density. Additionally, it showed lower surface roughness, higher film density, and enhanced wet etch resistance compared to films deposited using the PEALD process with non-magnetized plasmas. This improvement can be attributed to the higher ion flux and lower ion energy of the magnetized plasma. The electrical characteristics, such as interface trap density and breakdown voltage, were also enhanced when the magnetized plasma was used for the PEALD process. Furthermore, when SiN x films were deposited on high-aspect-ratio (30:1) trench patterns using the magnetized PEALD process, an improved step coverage of over 98% was achieved, in contrast to the conformality of SiN x deposited using non-magnetized plasma. This enhancement is possibly a result of deeper radical penetration enabled by the magnetized plasma.

Infrared Imaging Using Thermally Stable HgTe/CdS Nanocrystals.

Transferring nanocrystals (NCs) from the laboratory environment toward practical applications has raised new challenges. HgTe appears as the most spectrally tunable infrared colloidal platform. Its low-temperature synthesis reduces the growth energy cost yet also favors sintering. Once coupled to a read-out circuit, the Joule effect aggregates the particles, leading to a poorly defined optical edge and large dark current. Here, we demonstrate that CdS shells bring the expected thermal stability (no redshift upon annealing, reduced tendency to form amalgams, and preservation of photoconduction after an atomic layer deposition process). The electronic structure of these confined particles is unveiled using k.p self-consistent simulations showing a significant exciton binding energy of ∼200 meV. After shelling, the material displays a p-type behavior that favors the generation of photoconductive gain. The latter is then used to increase the external quantum efficiency of an infrared imager, which now reaches 40% while presenting long-term stability.

Catalytic atomic layer deposition of amorphous alumina–silica thin films on carbon microfibers

Deposition of silica-based thin films on carbon microfibers has long been considered a challenge. Indeed, the oxidation-sensitive nature of carbon microfibers over 550 K and their submicron-textured surface does not bode well with the required conformity of deposition best obtained by atomic layer deposition (ALD) and the thermal oxidative conditions associated with common protocols of silica ALD. Nonetheless, the use of a catalytic ALD process allowed for the deposition of amorphous alumina–silica bilayers from 445 K using trimethylaluminium and tris(tert-pentoxy)silanol (TPS). In this study, first undertaken on flat silicon wafers to make use of optical spectroscopies, the interplay between kinetics leading to a dense silica film growth was investigated in relation to the applied operation parameters. A threshold between the film catalyzed growth and the complete outgassing of pentoxy-derived compounds from TPS was found, resulting in a deposition of equivalent growth per cycle of 1.1 nm c−1, at a common ALD rate of 0.3 nm min−1, with a flat thickness gradient. The deposition on carbon microfiber fabrics was found conformal, albeit with a thickness growth capped below 20 nm, imparted by the microfiber surface texture. STEM-EDX showed a sharp interface of the bilayer with limited carbon diffusion. The conformal and dense deposition of alumina–silica thin films on carbon microfibers holds great potential for further use as refractory oxygen barrier layers.

Remote inductively coupled plasmas in Ar/N2 mixtures and implications for plasma enhanced ALD

Plasma enhanced atomic layer deposition (PEALD) is a cyclic atomic layer deposition (ALD) process that incorporates plasma-generated species into one of the cycle substeps. The addition of plasma is advantageous as it generally provides unique reactants and a substantially reduced growth temperature compared to thermal approaches. However, the inclusion of plasma, coupled with the increasing variety of plasma sources used in PEALD, can make these systems challenging to understand and control. This work focuses on the use of plasma diagnostics to examine the plasma characteristics of a remote inductively coupled plasma (ICP) source, a type of plasma source that is commonly used for PEALD. Ultraviolet to near-infrared spectroscopy and spatially resolved Langmuir probe measurements are employed to characterize a remote ICP system using nitrogen-based gas chemistries typical for III-nitride growth processes. Spectroscopy is used to characterize the relative concentrations of important reactive and energetic neutral species generated in the remote ICP as a function of gas flow rate, Ar/N2 flow fraction, and gas pressure. In addition, the plasma potential and plasma density for the same process parameters are examined using an RF compensated Langmuir probe downstream from the ICP source. The results are also discussed in terms of their impact on materials growth.

Controllable surface functionalization of rice husk-derived porous carbon by atomic layer deposition for highly-efficient microwave absorption

Multilayer absorbers, characterized by their distinctive structures and numerous heterogeneous interfaces, possess the potential to become exceptionally efficient and stable electromagnetic wave absorbers. Herein, we have ingeniously engineered multilayer ZnO/NiCo/C (ZNC) composite absorbers, utilizing a combination of an annealing procedure and atomic layer deposition (ALD) process. From the SEM images, the ZnO layers composed of ZnO nanoparticles (NPs) fabricated via ALD almost completely cover the surface of rice husk-derived carbon and the NiCo NPs residing on the surface. Benefiting from the specific multilayer structure, the well-designed ternary dielectric/magnetic components, and the synergistic interplay between dipole polarization relaxation and interfacial polarization relaxation, coupled with good impedance matching, the ZNC150 and ZNC200 composites exhibit best microwave absorption capacities. Through the precise control of the electromagnetic parameters by the deposition circle modifications, the minimum reflection loss reaches −52.5 dB and the effective bandwidth extends to 4.96 GHz with thin thickness of 1.52 mm.

Room temperature atomic layer deposition of zinc titanium oxide using sequential adsorption of dimethyl zinc and tetrakis(dimethylamino)titanium

Complex oxide films of TiO2 and ZnO are deposited by RT atomic layer deposition (ALD) with a sequential adsorption process. In this ALD, a Zn precursor of dimethyl zinc (DMZ) and a Ti precursor of tetrakis(dimethylamino)titanium (TDMAT) are used. In the sequential adsorption step, the DMZ saturation on the surface is followed by partial adsorption of TDMAT. It is assumed that the TDMAT molecule is adsorbed on the DMZ uncovered area. The mixed layer of DMZ and TDMAT is formed in the adsorption step, followed by being oxidized with the plasma-excited humidified Ar. All the ALD processes are performed at RT without any sample heating in the ALD chamber. The growth per cycle of the balanced Zn and Ti oxide deposition is recorded at 0.086 nm/cycle. The mixing ratio of Zn and Ti is controlled by the TDMAT exposure in the adsorption step. In this study, the reaction model and the related rate equations to calculate the mixing concentration ratio are proposed based on the in situ observation of the surface reaction by IR absorption spectroscopy.

Atomic-scale oxygen-vacancy engineering in Sub-2 nm thin Al2O3/MgO memristors

Ultrathin (sub-2 nm) Al2O3/MgO memristors were recently developed using an in vacuo atomic layer deposition (ALD) process that minimizes unintended defects and prevents undesirable leakage current. These memristors provide a unique platform that allows oxygen vacancies (VO) to be inserted into the memristor with atomic precision and study how this affects the formation and rupture of conductive filaments (CFs) during memristive switching. Herein, we present a systematic study on three sets of ultrathin Al2O3/MgO memristors with VO-doping via modular MgO atomic layer insertion into an otherwise pristine insulating Al2O3 atomic layer stack (ALS) using an in vacuo ALD. At a fixed memristor thickness of 17 Al2O3/MgO atomic layers (∼1.9 nm), the properties of the memristors were found to be affected by the number and stacking pattern of the MgO atomic layers in the Al2O3/MgO ALS. Importantly, the trend of reduced low-state resistance and the increasing appearance of multi-step switches with an increasing number of MgO atomic layers suggests a direct correlation between the dimension and dynamic evolution of the conducting filaments and the VO concentration and distribution. Understanding such a correlation is critical to an atomic-scale control of the switching behavior of ultrathin memristors.

Reaction mechanisms of α,ω-bifunctional molecules toward atomic layer deposition versus molecular layer deposition

Atomic layer deposition (ALD) and molecular layer deposition (MLD) are key techniques used to fabricate high-quality thin films. Organic α,ω-bifunctional precursors often exhibit different growth behaviors depending on the functional groups as well as the chain length of the molecular backbone, so that some organic precursors produce thin films of organic-inorganic hybrid materials, while others may deposit purely inorganic thin films without incorporation of the hydrocarbon moiety. In this study, we investigated the surface reaction mechanisms of α,ω-bifunctional molecules (X(CH2)nX, n = 2, 3, 4, 5, 6, and X = OH, SH, NH2) with diethylzinc toward MLD and ALD using density functional theory (DFT) calculations. It was found that the length of the aliphatic alkyl chain and the terminal functional groups of bifunctional organic precursors significantly influences their reactivity, resulting in the possibility toward removal or incorporation of the organic moiety in the product. Bifunctional reactants with longer alkyl backbones (n > 4) showed higher reactivity for removal of the hydrocarbon chain, facilitated by a ω-2 hydrogen transfer reaction. Furthermore, a reactivity trend of SH > OH > NH2 for removal of the hydrocarbon chains was observed. Our study provides in-depth theoretical insights into the adsorption reaction mechanisms occurring when bifunctional molecules are employed as organic reactants in ALD and MLD processes.

Analysis of ferroelectric properties of ALD-Hf0.5Zr0.5O2 thin films according to oxygen sources

Ferroelectric Hf0.5Zr0.5O2 (HZO) thin films are mostly deposited with a thickness of less than 10 nm by an atomic layer deposition (ALD) process. Since the oxygen source used in the ALD process affects the residues in the deposited HZO films, the choice of oxygen source can be one of the important factors to improve ferroelectricity. From this point of view, the ferroelectric properties of 10-nm-thick ALD-HZO films according to the oxygen source (O3, H2O, and D2O) were comprehensively analyzed in this study. Heavy water (deuterium water, D2O) was used as a tracer to pinpoint the origin of hydrogen that could be derived from unreacted metal precursors or unreacted hydroxyl groups. As a result, it was revealed that the decrease in ferroelectric polarization and increase in leakage current observed in the H2O- and D2O-based HZO capacitors compared to the O3-based HZO capacitor were due to the oxygen source. These results highlight the importance of using O3 as a hydrogen-free oxygen source in the ALD process to achieve better ferroelectricity.

Nanocavity-Mediated Purcell Enhancement of Er in TiO2 Thin Films Grown via Atomic Layer Deposition.

The use of trivalent erbium (Er3+), typically embedded as an atomic defect in the solid-state, has widespread adoption as a dopant in telecommunication devices and shows promise as a spin-based quantum memory for quantum communication. In particular, its natural telecom C-band optical transition and spin-photon interface make it an ideal candidate for integration into existing optical fiber networks without the need for quantum frequency conversion. However, successful scaling requires a host material with few intrinsic nuclear spins, compatibility with semiconductor foundry processes, and straightforward integration with silicon photonics. Here, we present Er-doped titanium dioxide (TiO2) thin film growth on silicon substrates using a foundry-scalable atomic layer deposition process with a wide range of doping controls over the Er concentration. Even though the as-grown films are amorphous after oxygen annealing, they exhibit relatively large crystalline grains, and the embedded Er ions exhibit the characteristic optical emission spectrum from anatase TiO2. Critically, this growth and annealing process maintains the low surface roughness required for nanophotonic integration. Finally, we interface Er ensembles with high quality factor Si nanophotonic cavities via evanescent coupling and demonstrate a large Purcell enhancement (≈300) of their optical lifetime. Our findings demonstrate a low-temperature, nondestructive, and substrate-independent process for integrating Er-doped materials with silicon photonics. At high doping densities this platform can enable integrated photonic components such as on-chip amplifiers and lasers, while dilute concentrations can realize single ion quantum memories.

Reliability Engineering of High‐Mobility IGZO Transistors via Gate Insulator Heterostructures Grown by Atomic Layer Deposition

AbstractThe reliability of oxide‐semiconductor (OS) thin‐film transistors (TFTs) is significantly influenced by the gate insulator (GI). During electrical bias stress, the defect sites near the semiconductor/GI interface and/or within the GI may trap electrons, which makes the threshold voltage (Vth) shift toward positive values. On the other hand, carbon (C) or hydrogen (H) atoms may diffuse from the GI into the active layer, and act as shallow donors, which induce negative Vth shifts (ΔVth). In this paper, an in situ atomic layer deposition (ALD)‐based GI heterostructure is introduced, which consists of a stack of two complementary materials, namely Al2O3 and SiO2. Here, a competition occurs between electron trapping in Al2O3 (positive ΔVth) and carrier generation from H atoms in SiO2 (negative ΔVth) which allows the achievement of nearly zero ΔVth under positive bias temperature stress (PBTS). This strategy is successfully applied to a high‐mobility (&gt;50 cm2 Vs−1) ALD‐based indium‐gallium‐zinc oxide (IGZO) device, resulting in a net ∆Vth of −0.02 V under PBTS and drain current variation (∆ID) of +0.49% under constant current stress (CCS). The application of an in situ ALD process thus offers valuable insights to resolve the mobility versus reliability trade‐off in high‐performance oxide TFTs.

Study on the Sodium-Doped Titania Interface-Type Memristor.

Memristors integrated into a crossbar-array architecture (CAA) are promising candidates for analog in-memory computing accelerators. However, the relatively low reliability of the memristor device and sneak current issues in CAA remain the main obstacles. Alkali ion-based interface-type memristors are promising solutions for implementing highly reliable memristor devices and neuromorphic hardware. This interface-type device benefits from self-rectifying and forming-free resistive switching (RS), and exhibits relatively low variation from device to device and cycle to cycle. In a previous report, we introduced an in situ grown Na/TiO2 memristor using atomic layer deposition (ALD) and proposed a RS mechanism from experimentally measured Schottky barrier modulation. Self-rectifying RS characteristics were observed by the asymmetric distribution of Na dopants and oxygen vacancies as the Ti metal used as the adhesion layer for the bottom electrode diffuses over the Pt electrode at 250 °C during the ALD process and is doped into the TiO2 layer. Here, we theoretically verify the modulation of the Schottky barrier at the TiO2/Pt electrode interface by Na ions. This study fabricated a Pt/Na/TiO2/Pt memristor device and confirmed its self-rectifying RS characteristics and stable retention characteristics for 24 h at 85 °C. Additionally, this device exhibited relative standard deviations of 27 and 7% in the high and low resistance states, respectively, in terms of cycle-to-cycle variation. To verify the RS mechanism, we conducted density functional theory simulations to analyze the impact of Na cations at interstitial sites on the Schottky barrier. Our findings can contribute to both fundamental understanding and the design of high-performance memristor devices for neuromorphic computing.