Deposition Of Y2O3 Research Articles

Atomic layer deposition of Y2O3 as high-k dielectrics by using a heteroleptic yttrium precursor and water

Atomic layer deposition (ALD) of Y2O3 thin films was performed on Si substrate by pulsing an unconventional heteroleptic yttrium precursor Y(MeCp)2(Me2Pz) and H2O alternatively. The thin film grew 0.26–0.28 Å per cycle at relatively low temperature of 195–225 °C in a self-limiting manner with negligible nucleation delay, and is close to stoichiometric (O/Y = 1.48, C, 2.56 at%; N, 1.81 at%) in as-deposited form. Integration of the post-annealed ALD Y2O3 film in a metal oxide semiconductor (MOS) capacitor structure exhibits representative electrical properties including a high dielectric constant k of 11.4, high electrical breakdown field of 6.1 MV cm−1 and low leakage current density of 9.1 × 10−8 A cm−2 at − 2 MV cm−1.

Synergistic effect of water solubility sulfhydryl compound and rare-earth ions on the microstructure, composition, and corrosion resistance of brass

The aim of the present research is to develop one new strategy to modify the brass surface with well anticorrosion performance. Here, utilizing the synergistic effect between thioglycolic acid (TGA) and Y(III), one organic–inorganic hybrid film composed of a self-assembled film at the top and an oxide film at the bottom was fabricated on brass surface. The formation process of the hybrid film contained the parallel adsorption of TGA molecules, surface oxidation of copper accompanied by zinc dissolution, interface deposition of Y2O3 and assembly of Cu-TGA chelates. Electrochemical results indicated that the protection efficiency was 99.2% under the optimum conditions and the value remained at 92.1% after 12 h immersion in 3.5 wt% NaCl solution. Due to the good water solubility of the film-forming substance and excellent anticorrosion performance of the fabricated film, this strategy has important application potential in the field of surface functionalization of copper alloys.

Diverse Coordination Chemistry of the Whole Series Rare-Earth L-Lactates: Synthetic Features, Crystal Structure, and Application in Chemical Solution Deposition of Ln2O3 Thin Films.

Rare-earth (RE, Ln) carboxylates are widely studied as precursors of RE oxide-based nanomaterials; however, no systematic studies of RE L-lactates (HLact = 2-hydroxypropanoic acid) have been reported to date. In the present work, a profound structural investigation of RE L-lactates is carried out. A family of RE lactate complexes of the general formula LnLact3∙nH2O (Ln = La, Ce-Nd, Sm-Lu, Y; n = 2-3) are synthesized and characterized by CHN, TGA, and FTIR as well as by powder and single-crystal XRD methods.The existence of four novel structural types (1-Ln-4-Ln) is revealed. Compounds of the 1-Ln type (Ln = La, Ce, Pr) exhibit a chain polymeric structure, whereas 2-Ln-4-Ln compounds are molecular crystals consisting of dimeric (2-Ln; Ln = La, Ce-Nd) or monomeric (3-Ln-Ln = Sm-Lu, Y; 4-Ln-Ln = Sm-Gd, Y) species. The crystal structures of 1-Ln-4-Ln compounds are discussed in terms of their coordination geometry and supramolecular arrangement. Solutions of yttrium and lanthanum lactates with diethylenetriamine are applied for the chemical deposition of Y2O3 and La2O3 thin films.

Y2O3 electrodeposited TiO2 nanotube arrays as photoanode for enhanced photoelectrochemical water splitting

Y2O3 deposited TiO2 nanotubes (Y-TNTs) are investigated as photoanodes for efficient photoelectrochemical water splitting. Y2O3 is electrodeposited on TiO2 nanotubes for 5–15 min. The physicochemical and optical properties of Y-TNTs reveal that Y2O3 anchored on the TNTs enhances the visible light absorption. The Y-TNTs show good photocurrent response compared to pristine TNTs. Y2O3 deposition for 10 min on TNTs produces highest photocurrent of 609 μA cm−2 at 1.23 VRHE. Presence of Y2O3 increases the lifetime of the charge carriers as revealed by the Nyquist plot analysis and Mott-Schottky analysis. Y-TNTs-10 min sample shows 2.75 times higher photoconversion efficiency compared to pristine TNTs. Computational analysis shows that Y–TiO2 has negative free energy of adsorption for OER intermediates as compared to bare TiO2 which has positive values. The rare earth metal electrodeposition on TiO2 nanotubes is another approach to improve the photoelectrochemical water splitting activity without distorting the nanotube structure.

Effect of ZRO2 and Y2O3 Deposition on Biological Behavior of Ti-Base Alloys

Titanium has a good ability to attach to bone and living tissue, making it a perfect material for orthopedic implants. Because of the combination of high resistance to corrosion, biocompatibility and excellent mechanical properties. This work aims to study the Modifications of various base titanium implant samples producing by using powder technology (Ti-pure, Ti-45 % Ni, Ti10 % Co, and Ti-30 % Ta) by deposition of Nano Zirconia and yttria powders (70 % and 30% ). Chemical pretreatment carried out to prepare the implant surface before deposition, while the deposition process accomplished by pack cementation. The Characterizations of samples accomplished before and after the surface treatment, which includes: microstructure observation, x-ray diffraction (XRD), MTT Assay (cell viability) and MTT assay (cell adhesion). From the SEM All samples Show that Nano Zirconia and yttria were homogeneously put on the surface and fully covered it which resulted in a substantial modification in surface morphologies. From XRD patterns the peaks slightly shifted to the low angle side also amorphous behavior was observed. From MTT graphs it was found that the titanium alloys surface after pack cementation became more active after 3 days of exposure in MG-63 cells and there was a remarkable increase in cell viability and cell attachment compared with untreated samples.

Electrical Characteristics of Atomic Layer Deposited Y-Silicate Dielectrics

Introduction High k dielectric materials are widely used for scaling the equivalent oxide thickness (EOT) of various very large integrated devices. Rare-earth silicates maintain their amorphous structure within the temperature range of typical semiconductor processes [1] , making them suitable for high-k dielectrics. Rare-earth silicates are easily formed by thermal processes, but their formation consumes Si at the interface. The consumption of Si at the interface is disadvantageous for micro-structured devices such as three-dimensional structures. One of the methods to suppress Si consumption at the interface is to supply Si atoms in the deposited film to form silicates without reacting with the channel material. In this work, we focused on the formation of yttrium silicate (Y-silicate) dielectrics, a typical rare-earth silicate [2] , so that the formation process can be easily extended to other rare-earth silicates, including La-silicate [3] .Y-silicate films were formed by cyclic deposition of Y2O3 and SiO2 based on atomic-layer deposition (ALD). Experiments Firstly, Y2O3/SiO2 multi-stacked layer（call it stacked-layer from now on）with a thickness of 16 nm without annealing process was analyzed by x-ray photoelectron spectroscopy (XPS) to confirm forming of Y-silicates. Next, MOS capacitor was fabricated by stacked-layer with a thickness 5 nm were deposited on the n-Si substrates by ALD at 200oC. Fig. 1 shows the schematic structure of the fabricated MOS capacitors. The cycles are determined to have the Y/Si atomic ratio of the stacked-layer to be 1:1. Then, W gate electrodes and TiN layer are deposited by RF sputtering. Al contact layers were deposited on the backside of the samples by thermal evaporation. The capacitors were then annealed at 800oC in forming gas (N2: H2=97%:3%) ambient for 30 min. [4] Finally, the metal-insulator-metal (MIM) capacitor, 10-nm-thick stacked-layer were also fabricated aim to no interfacial layer. Result Fig.2 shows the results of XPS analysis. The shift in the binding energy indicates that most of the Y atoms are in the form of silicate. Suggesting that the stacked layer is readily transformed in the form of Y-silicate during ALD process. The bandgap of the stacked-layer was estimated to be 6.4 eV. Fig. 3 shows the XPS depth profile of the stacked-layer obtained by Ar etching. The atomic ratio of Y, Si and O remained constant throughout the film at almost 2:2:7 until the Si substrate appeared. From the results, it is confirmed that a uniform Y2Si2O7 layer can be obtained by the multi-stacking of Y2O3/SiO2 ALD process. Fig. 4 shows the C-V characteristics of the n-Si capacitors with a 5-nm-thick Y-silicate layer. After annealing, the capacity of Y-silicate layer capacitor doesn’t increase. This result indicating little reaction at Y-silicate/Si interface. Finally, from the C-V and J-V measurements of MIM capacitor, A k-value of the stacked-layer is calculated to be 8.5, break down field of MIM capacitor is 6.6MV/cm. The k-value of the Y-silicate layer is also reasonable considering the k-values of SiO2 of 3.9 and Y2O3 of 13. [5] Conclusion Low temperature formation of Y-silicate layer has been confirmed by cyclic deposition of stacked-layer of Y2O3 and SiO2 ALD layers. The target composition of Y2Si2O7 and the formation of Y-O-Si bonds have been confirmed by XPS. Bandgap, breakdown field and k-value of Y-silicate dielectrics were determined to be 6.4eV, 6.6MV/cm, 8.5 respectively.

Reduction of MOS Interface Defects in TiN/Y₂O₃/Si₀.₇₈Ge₀.₂₂ Structures by Trimethylaluminum Treatment

We report improvement of TiN/Y2O3/ Si0.78Ge0.22 metal-oxide-semiconductor (MOS) interface properties by employing the trimethylaluminum (TMA) pretreatment before Y2O3 deposition. It is found that the optimum number of the TMA pretreatment cycles for minimizing interface trap density ( ${D}_{\text {it}}$ ) and slow trap density ( $\Delta {N}_{\text {st}}$ ) of TiN/Y2O3/SiGe interfaces with post metallization annealing (PMA) at 450 °C is ten cycles. The reduction in ${D} _{\text {it}}$ and $\Delta ~{N} _{\text {st}}$ is attributable to less amounts of Ge–O bonds at the SiGe interfaces. On the other hand, an increase in ${D} _{\text {it}}$ with further increasing the number of TMA pretreatment is attributable to more amounts of Al–O bonds in ILs.

Electrophoretically Deposited Y2O3:Bi3+,Yb3+ Nanosheet Films as Spectral Converters for Crystalline Silicon Solar Devices

Transparent Y2O3:Bi3+,Yb3+ films that exhibit near-infrared (NIR) emission under near-ultraviolet (NUV) excitation are candidates for the spectral converters in crystalline silicon solar devices. In this work, NIR-emitting films were fabricated by the aqueous electrophoretic deposition of Y2O3:Bi3+,Yb3+ nanosheets, and their photoluminescence (PL) properties were enhanced by a postcalcination process. Positively charged Y2O3:Bi3+,Yb3+ nanosheets with adsorbed polyethylenimine (PEI) were deposited as a uniform and dense micrometer thick layer on a transparent conductive substrate by applying an electric field to an aqueous nanosheet dispersion. The resulting nanosheet film showed NIR emission from Yb3+, realized through energy transfer from Bi3+, when excited under NUV light. The NIR PL intensity of the film was improved by calcination at 700–1000 °C under a flow of air. This NIR PL enhancement was explained by the calcination process increasing the crystallinity of the Y2O3:Bi3+,Yb3+ nanosheets and removing adsorbed hydroxyl groups that quenched the NIR emission of Yb3+. Furthermore, the increased energy transfer efficiency of the Bi3+ → Yb3+ transition with increasing calcination temperature also contributed to the observed NIR PL enhancement of the nanosheet film. The NIR PL intensity of the as-deposited nanosheet film did not change under continuous NUV excitation, whereas a gradual increase in the PL intensity was observed for the calcined nanosheet films. This increase in the PL intensity of the calcined films would be caused by the photooxidation of the Bi and Yb ions, which were partially reduced by PEI during the calcination process.

Y(dbm)3(H2O)]: Synthesis, thermal behavior and spin-coating precursor for Y2O3 layer formation

The synthesis, structure and thermal behavior of [Y(dbm)3(H2O)] (3) (dbm = 1,3-diphenyl-1,3-propandionate) and its use as a spin-coating precursor for Y2O3 deposition is reported. Complex 3 was prepared by the reaction of [Y(NO3)3·6H2O] (1) with 3 equiv of Hdbm (2) in presence of NaOH. The molecular structure of 3 in the solid-state was determined by single X-ray crystal diffraction. Both C1 symmetric crystallographically independent species of 3 possess a YO7 coordination setup with minor deviation from an ideal capped octahedron coordination geometry (Λ enantiomer). Complex 3 forms a 1D chain, due to intermolecular hydrogen bonds between the coordinated H2O molecule and the O atom of the dbm ligand, respectively. The thermal decomposition behavior of 3 was investigated by thermogravimetric studies in the temperature range of 40–800 °C and 40–1300 °C under an oxygen and argon atmosphere, respectively. Powder X-ray diffraction (PXRD) measurements of the residues confirmed the formation of Y2O3. Complex 3 was applied as a spin-coating precursor for yttrium oxide film formation on either Si wafers with a continuous 100 nm thick SiO2 film, or with a native oxide layer. The as-deposited Y2O3 layers are smooth, conformal, dense and transparent and are of a thickness of 27 and 30 nm, respectively.

Atomic layer deposition of Y2O3 on h-BN for a gate stack in graphene FETs

The combination of h-BN and high-k dielectrics is required for a top gate insulator in miniaturized graphene field-effect transistors because of the low dielectric constant of h-BN. We investigated the deposition of Y2O3 on h-BN using atomic layer deposition. The deposition of Y2O3 on h-BN was confirmed without any buffer layer. An increase in the deposition temperature reduced the surface coverage. The deposition mechanism could be explained by the competition between the desorption and adsorption of the Y precursor on h-BN due to the polarization. Although a full surface coverage was difficult to achieve, the use of an oxidized metal seeding layer on h-BN resulted in a full surface coverage.

Characterization of amorphous yttria layers deposited by aqueous solutions of Y-chelate alkoxides complex

Crack-free amorphous yttria layers were deposited by dip coating in solutions of different Y-chelate alkoxides complex. Three Y-chelate solutions of different concentrations were prepared using yttrium acetate tetrahydrate, yttrium stearic acid as Y source materials. PEG, diethanolamine were used as chelating agents, while ethanol, methanol and tetradecane were used as solvent. Three different combinations of chelating and solvents were used to prepare solutions for Y2O3 dip coating on SUS, electropolished and non-electropolished Hastelloy C-276 substrates. The thickness of the films was varied by changing the number of dipping cycles. At an optimized condition, the substrate surface roughness (rms) value was reduced from ∼50nm to ∼1nm over a 10×10μm2 area. After Y2O3 deposition, MgO was deposited using ion-beam assisted deposition (IBAD), then LaMnO3 (LMO) was deposited using sputtering and GdBCO was deposited using reactive co-evaporation by deposition and reaction (RCE-DR). Detailed X-ray study indicates that LMO/MgO/Y2O3 and GdBCO/LMO/MgO/Y2O3 stack films have good out-of-plane and in-plane textures with strong c-axis alignment. The critical current (Ic) of GdBCO/LMO/MgO/Y2O3 multilayer structure varied from 190 to 420A/cm with different solutions, when measured at 77K. These results demonstrated that amorphous yttria can be easily deposited by dip coating using Y-chelates complex as a diffusion barrier and nucleation layer.

Magnetic and luminescent Fe3O4/Y2O3:Eu3+ composites with hollow spheres and mesoporous silica

In this paper, co-precipitation synthesized Fe3O4 microspheres have been encapsulated with nonporous silica and further functionalized by the deposition of Y2O3:Eu3+ phosphors through a simple co-precipitation process, realizing a hollow structured material with mesoporous, magnetic and luminescent properties. The results reveal that the material shows typical ordered mesoporous characteristics, and have monodisperse spherical morphology with smooth surface and narrow size distribution. Additionally, the multifunctional nanocomposite shows the characteristic emission of Eu3+ (5D0–7F1–4). Magnetism measurement reveals the paramagnetic feature of the samples. Furthermore, we also compared the magnetic and fluorescent properties of solid Fe3O4@SiO2@Y2O3:Eu3+ and Fe3O4@HM-SiO2@Y2O3:Eu3+.

Atomic layer deposition of Y2O3 and yttrium-doped HfO2 using a newly synthesized Y(iPrCp)2(N-iPr-amd) precursor for a high permittivity gate dielectric

We systematically investigated the effects of Y doping in HfO2 dielectric layer, focusing on structural phase transformation and the dielectric properties of the resultant films. Y doping was carried out using atomic layer deposition (ALD) with a novel Y(iPrCp)2(N-iPr-amd) precursor, which exhibits good thermal stability without any decomposition and clean evaporation. As a result, the ALD process of the Y2O3 films showed well-saturated and linear growth characteristics of ∼0.45Å/cycle without significant incubation delays and produced pure Y2O3 films. Then, yttrium-doped HfO2 films with various Y/(Y+Hf) compositions (yttrium content: 0.6– 4.8mol%) were prepared by alternating Y2O3 and HfO2 growth cycles. Structural and electrical characterization revealed that the addition of yttrium to HfO2 induced phase transformations from the monoclinic to the cubic or tetragonal phases, even at low post-annealing temperatures of 600°C, and improved leakage current densities by inducing oxygen vacancy-related complex defects. A maximum relative dielectric constant of ∼33.4 was obtained for films with a yttrium content of ∼1.2mol%. Excellent EOT scalability was observed down to ∼1nm without dielectric constant degradation.

RF plasma MOCVD of Y2O3 thin films: Effect of RF self-bias on the substrates during deposition

Yttrium oxide (Y2O3) thin films have been deposited by radio frequency plasma assisted metal organic chemical vapor deposition (MOCVD) process using (2,2,6,6-tetramethyl-3,5-heptanedionate) yttrium (commonly known as Y(thd)3) precursor in a plasma of argon and oxygen gases at a substrate temperature of 350°C. The films have been deposited under influence of varying RF self-bias (−50V to −175V) on silicon, quartz, stainless steel and tantalum substrates. The deposited coatings are characterized by glancing angle X-ray diffraction (GIXRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), spectroscopic ellipsometry and scanning electron microscopy (SEM). GIXRD and FTIR results indicate deposition of Y2O3 (BCC structure) in all cases. However, XPS results indicate nonstoichiometric cubic phase deposition on the surface of deposited films. The degree of nonstoichiometry varies with bias during deposition. Ellipsometry results indicate that the refractive index for the deposited films is varying from 1.70 to 1.83 that is typical for Y2O3. All films are transparent in the investigated wavelength range 300–1200nm. SEM results indicate that the microstructure of the films is changing with applied bias. Results indicate that it is possible to deposit single phase cubic Y2O3 thin films at low substrate temperature by RF plasma MOCVD process. RF self-bias that decides about the energy of impinging ions on the substrates plays an important role in controlling the texture of deposited Y2O3 films on the substrates. Results indicate that to control the structure of films and its texture, it is important to control the bias on the substrate during deposition. The films deposited at high bias level show degradation in the crystallinity and reduction of thickness.

Multifunctional nanocomposites with different coupling agents: synthesis, luminescent and magnetic properties

In this study, the co-precipitation method has been developed for the synthesized Fe3O4 nanoparticles which are encapsulated with SiO2/C/TiO2 via the facile and further functionalized by the deposition of Y2O3:Eu3+ phosphors. Transmission electron microscopy images revealed that the nanocomposites show a spherical morphology with size distribution around 100–250 nm, and the thickness of the coupling agents was 3–4 nm. The X-ray diffraction patterns showed that a cubic spinel structure of Fe3O4 core and a tetragonal phase of Y2O3:Eu3+ shell was obtained. The multifunctional nanocomposites showed ferrimagnetic behavior, the negligible coercivity Hc and remanence Mr at room temperature and showed unique europium fluorescence properties with strong red emission peak from the electric–dipole transition 5D0 → 7F2 of Eu3+ ions at 611 nm. Therefore, the multifunctional nanocomposites are expected to develop many potential applications in biomedical fields and magnetic photocatalyst.

Targetry of Y2O3 on a copper substrate for the non-carrier-added 89Zr production via 89Y(p, n)89Zr reaction

Abstract A thick layer of Yttrium oxide was deposited on cupper substrate via two special sedimentation methods for the production of 89Zr. For deposition of Y2O3 on cupper substrate, 435 mg of Y2O3, 152.25 mg of ethyl cellulose and 4 ml of acetone were used to prepare a Y2O3 layer of 11.69 cm2. Also, 435 mg of Y2O3, 174 mg of methyl cellulose and 7.25 ml of water were used. The targets were checked by SEM and thermal shock test. The deposited target was irradiated for 20 min at a current of 20 μA and a proton beam of 15 MeV.

Flame aerosol deposition of Y2O3:Eu nanophosphor screens and their photoluminescent performance

Screens of Y2O3:Eu3 + -nanophosphor (dBET = 24 nm) with coating densities in the range 0.23–3.8 mg cm − 2 were obtainedby flame aerosol deposition (FAD) from nitrate-based precursors. The average deposition rate was 0.22 mg cm − 2 min − 1. Porosity of theobtained deposits was 0.973 ± 0.004. Light scattering of the coatings in the visible range showed a Rayleigh-like dependence on wavelengthand, in comparison to the screens made of the commercial micrometer-sized phosphor powder (dSEM = 4 µm), was reduced by up to two orders of magnitude. As a result, the nanophosphor coatingsmaintained nearly constant brightness in a very wide range of coating densities. Furthermore, itshould be expected that a substantially improved screen resolution can be achieved with suchscreens. For excitation at a wavelength of 254 nm, the maximum brightness of the FAD-deposited(Y0.92Eu0.08)2O3 phosphor screens in the transmission mode was nearly one third of that of the screens madeof the commercial phosphor. It was demonstrated that light reflection from the supportingsubstrate and porosity of the coating significantly influence its photoluminescentperformance.

Microwave electron cyclotron resonance plasma metal organic chemical vapour deposition of Y2O3 coatings

Y2O3 thin films were deposited on Si (111) and s.s. substrates by microwave electron cyclotron resonance (ECR) plasma metal organic chemical vapour deposition (MOCVD) using a Y(thd)3 (thd = 2,2,6,6,-tetramethyl-3,5-heptanedionate) precursor at a substrate temperature of 450 C. The deposited coatings were characterized by x-ray photoelectron spectroscopy (XPS). From the observed binding energies of the photoelectrons Y 3d5/2, Y 3d3/2 and O 1s, deposition of Y2O3 coating on the substrates is confirmed. Along with Y2O3 some carbon deposition is also seen. Oxygen plasma annealing of the deposited coatings with increase in the substrate temperature shows reduction in the carbon content in the coating. Details regarding deposition experiments, effects of oxygen plasma annealing and characterization of coatings are discussed in this paper.

Comparative study of synthesis and characterization of monodispersed SiO2 @ Y2O3:Eu3+ and SiO2 @ Y2O3:Eu3+ @ SiO2 core–shell structure phosphor particles

Abstract Monodispersed SiO2 @ Y2O3:Eu3+ and SiO2 @ Y2O3:Eu3+ @ SiO2 nanospheres contain SiO2 as core and Y2O3:Eu3+ as shell or another SiO2 shell coated on the surface of SiO2 @ Y2O3:Eu3+ particles were synthesized, respectively. The synthesis of core–shell particles SiO2 @ Y2O3:Eu3+ involved the SiO2 core ultrasonically dispersed into a certain amount of polyethylene glycol solution, and the deposition of Y2O3:Eu3+ on the surface of SiO2 core through homogeneous precipitation of Y3+ and Eu3+ using urea as precipitator. More over, the particles SiO2 @ Y2O3:Eu3+ as core was ultrasonically dispersed into a certain amount of ethanol and followed by sol–gel processing of tetraethoxysilane to form another silica shell. The morphology structures and sizes of the resulting particles were analyzed by SEM and TEM, which indicated that the resulting particles dispersed regularly and the microstructures of the particles are clearly core–shell or core–shell–shell structures. XRD patterns characterized the crystal structures of deposited Y2O3:Eu3+ shell or SiO2 shell after heat treatment at 900 °C. Photoluminescence determination showed that both the phosphors can be excited by ultra violet at 254 nm which showed red-shift. Under the excitation at 254 nm, the Eu3+ ion mainly shows its characteristic red (612 nm, 5D0–7F2) emission in the particles from Y2O3:Eu3+ shell. The emission intensity of Eu3+ was affected by the SiO2 core or shell in some extent.

Band alignment of yttrium oxide on various relaxed and strained semiconductor substrates

In this work, we report on the band offsets of yttrium oxide (Y2O3) on various relaxed and strained semiconductor substrates, such as silicon (Si), germanium (Ge), and silicon germanium (SiGe). By using the example of Y2O3/Si, important experimental aspects in using photoemission to determine band offsets are discussed. We then discuss the various values of band offsets of Y2O3 on the different substrates that we obtained by using x-ray photoelectron spectroscopy. Finally, we show that presputtering 3 Å of metallic Y [equivalent to 1 ML (monolayer) coverage] before the deposition of Y2O3 affects the band lineup by reducing the resultant valence band offsets. We explain the observed band offsets by using an interfacial layer model.