ORCID Profile
0000-0001-6255-391X
Current Organisation
Silanna Semiconductor
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Publisher: Springer Science and Business Media LLC
Date: 04-2016
DOI: 10.1038/SREP23843
Abstract: Phase Change Materials (PCMs) are unique compounds employed in non-volatile random access memory thanks to the rapid and reversible transformation between the amorphous and crystalline state that display large differences in electrical and optical properties. In addition to the amorphous-to-crystalline transition, experimental results on polycrystalline GeSbTe alloys (GST) films evidenced a Metal-Insulator Transition (MIT) attributed to disorder in the crystalline phase. Here we report on a fundamental advance in the fabrication of GST with out-of-plane stacking of ordered vacancy layers by means of three distinct methods: Molecular Beam Epitaxy, thermal annealing and application of femtosecond laser pulses. We assess the degree of vacancy ordering and explicitly correlate it with the MIT. We further tune the ordering in a controlled fashion attaining a large range of resistivity. Employing ordered GST might allow the realization of cells with larger programming windows.
Publisher: The Electrochemical Society
Date: 2002
DOI: 10.1149/1.1483101
Publisher: IEEE
Date: 06-2017
Publisher: IOP Publishing
Date: 25-07-2013
DOI: 10.1088/0953-8984/25/34/345801
Abstract: Sb-Te layers having various compositions between Sb2Te3 and Sb2Te are grown using molecular beam epitaxy. The structural and electrical properties of the layers change gradually with composition but exhibit a discontinuity involving a bistability. The holes in the layers are generated by Sb bilayers intercalated between Sb2Te3 quintuple layers and their mobility is governed by the scattering from the parent acceptors. Magnetoresistance for compositions around SbTe is linear, for which the reduction of the parabolic component due to low mobility is crucial. Density functional calculations predict Sb2Te3 and SbTe to be topological insulators (TIs) resembling Bi2Se3 and Bi2Te3, respectively. The prefactor of the weak antilocalization effect is α =- 1 regardless of the composition. The Sb-Te system is thus a family of TIs possessing undisturbed surface states for which the location of the Dirac point with respect to the bulk band gap is adjustable.
Publisher: AIP Publishing
Date: 06-08-2012
DOI: 10.1063/1.4742919
Publisher: IOP Publishing
Date: 22-10-2009
Publisher: Elsevier BV
Date: 11-2001
Publisher: AIP Publishing
Date: 15-06-2009
DOI: 10.1063/1.3152796
Abstract: Films of hexagonal praseodymium sesquioxide (h-Pr2O3) were deposited on Si(111) by molecular beam epitaxy and thereafter annealed in 1 atm oxygen at different temperatures, ranging from 100 to 700 °C. The films of the s les annealed at 300 °C or more were transformed to PrO2 with B-oriented Fm3¯m structure, while films annealed at lower temperatures kept the hexagonal structure. The films are composed of PrO2 and PrO2−δ species, which coexist laterally and are tetragonally distorted due to the interaction at the interface between oxide film and Si substrate. Compared to PrO2, PrO2−δ has the same cubic structure but with oxygen vacancies. The oxygen vacancies are partly ordered and increase the vertical lattice constant of the film, whereas the lateral lattice constant is almost identical for both species and on all s les. The latter lattice constant matches the lattice constant of the originally crystallized hexagonal praseodymium sesquioxide. That means that no long range reordering of the praseodymium atoms takes place during the phase transformation.
Publisher: IOP Publishing
Date: 07-11-2008
Publisher: AIP Publishing
Date: 06-2014
DOI: 10.1063/1.4881735
Abstract: In this paper, using a resonance-enhanced piezoresponse force microscopy approach supported by density functional theory computer simulations, we have demonstrated the ferroelectric switching in epitaxial GeTe films. It has been shown that in films with thickness on the order of several nanometers reversible reorientation of polarization occurs due to swapping of the shorter and longer Ge-Te bonds in the interior of the material. It is also hinted that for ultra thin films consisting of just several atomic layers weakly bonded to the substrate, ferroelectric switching may proceed through exchange of Ge and Te planes within in idual GeTe layers.
Publisher: American Chemical Society (ACS)
Date: 13-05-2014
DOI: 10.1021/NL5011492
Abstract: Sb2Te3 films are used for studying the epitaxial registry between two-dimensionally bonded (2D) materials and three-dimensional bonded (3D) substrates. In contrast to the growth of 3D materials, it is found that the formation of coincidence lattices between Sb2Te3 and Si(111) depends on the geometry and dangling bonds of the reconstructed substrate surface. Furthermore, we show that the epitaxial registry can be influenced by controlling the Si(111) surface reconstruction and confirm the results for ultrathin films.
Publisher: IOP Publishing
Date: 03-03-2011
DOI: 10.1088/0953-8984/23/11/115904
Abstract: Thin heteroepitaxial praseodymia films with fluorite structure on Si(111) were annealed under ultra-high vacuum conditions at temperatures in the region of 100 up to 300 °C. Afterward investigations by x-ray diffraction, grazing incidence x-ray diffraction and x-ray reflectometry were performed to obtain information about structural changes of the film during the annealing process. For this reason, praseodymia Bragg peaks were carefully analyzed within the kinematic diffraction theory. This analysis demonstrates the coexistence of different praseodymia phases depending on the conditions of preparation. Here, annealing of the s les up to 150 °C leads to a homogeneous film with a PrO(1.833) phase and with negligible strain since both the lateral and vertical lattice parameters nearly match the corresponding bulk praseodymia phase. Further annealing leads to oxygen loss accompanied by significantly increased lattice parameters. Since the lateral lattice parameter is pinned at the interface, the vertical lattice constant has to increase considerably due to the tetragonal distortion of the film. This causes the decomposition of the film into two oxide species with significantly different oxygen contents. Annealing at 300 °C reduces the film almost completely to PrO(1.5) which has the minimum content of oxygen.
Publisher: Elsevier BV
Date: 04-2022
Publisher: American Vacuum Society
Date: 2009
DOI: 10.1116/1.3043540
Abstract: Single crystalline epitaxial Si(111)/Y2O3(111)/Si(111) heterostructures were grown by molecular beam epitaxy and the morphology, structure, and defects were characterized in detail. The growth of a closed and smooth layer system is demonstrated by means of reflection high energy electron diffraction measurements. X-ray reflectometry and high resolution Rutherford backscattering (RBS) experiments show low surface and interface roughnesses. Channeling RBS as well as x-ray diffraction pole figure studies demonstrate the type A/B/A epitaxy relationship of the Si(111)/Y2O3(111)/Si(111) heterostructure and reveal the existence of defects in the epitaxial Si(111) layer. These defects are studied in detail with high resolution transmission electron microscopy, disclosing microtwin formation and type B Si grains as the major defects.
Publisher: AIP Publishing
Date: 02-2009
DOI: 10.1063/1.3068198
Abstract: Engineered wafer systems are an important materials science approach to achieve the global integration of single crystalline Ge layers on the Si platform. Here, we report the formation of single crystalline, fully relaxed Ge(111) films by molecular beam epitaxial overgrowth of cubic Pr oxide buffers on Si(111) substrates. Reflection high-energy electron diffraction, scanning electron microscopy, and x-ray reflectivity show that the Ge epilayer is closed, flat, and has a sharp interface with the underlying oxide template. Synchrotron radiation grazing incidence x-ray diffraction and transmission electron microscopy reveal the type-A/B/A epitaxial relationship of the Ge(111)/cubic Pr2O3(111)/Si(111) heterostructure, a result also corroborated by theoretical ab initio structure calculations. Secondary ion mass spectroscopy confirms the absence of Pr and Si impurities in the Ge(111) epilayer, even after an annealing at 825 °C.
Publisher: Wiley
Date: 24-11-2015
Abstract: Photoelectron spectroscopy in combination with piezoforce microscopy reveals that the helicity of Rashba bands is coupled to the nonvolatile ferroelectric polarization of GeTe(111). A novel surface Rashba band is found and fingerprints of a bulk Rashba band are identified by comparison with density functional theory calculations.
Publisher: Wiley
Date: 24-09-2011
DOI: 10.1002/SIA.3643
Publisher: Wiley
Date: 11-09-2007
DOI: 10.1002/SIA.2599
Publisher: AIP Publishing
Date: 10-2010
DOI: 10.1063/1.3486217
Abstract: Strained and relaxed single crystalline Si on insulator systems is an important materials science approach for future Si-based nanoelectronics. Layer transfer techniques are the dominating global integration approach over the whole wafer system but are difficult to scale down for local integration purposes limited to the area of the future device. In this respect, the heteroepitaxy approach by two simple subsequent epitaxial deposition steps of the oxide and the Si thin film is a promising way. We introduce tailored (Pr2O3)1−x(Y2O3)x oxide heterostructures on Si(111) as flexible heteroepitaxy concept for the integration of either strained or fully relaxed single crystalline Si thin films. Two different buffer concepts are explored by a combined experimental and theoretical study. First, the growth of fully relaxed single crystalline Si films is achieved by the growth of mixed PrYO3 insulators on Si(111) whose lattice constant is matched to Si. Second, isomorphic oxide-on-oxide epitaxy is exploited to grow strained Si films on lattice mismatched Y2O3/Pr2O3/Si(111) support systems. A thickness dependent multilayer model, based on Matthew’s approach for strain relaxation by misfit dislocations, is presented to describe the experimental data.
Publisher: Trans Tech Publications, Ltd.
Date: 10-2009
DOI: 10.4028/WWW.SCIENTIFIC.NET/SSP.156-158.467
Abstract: Silicon and germanium films epitaxially grown on metal oxide buffer layers on Si(111) substrates are characterized by different X-ray techniques, transmission electron microscopy and Raman spectroscopy. Pr2O3 and Y2O3 or a combination of both is used as buffer material. X-ray pole figure measurements and grazing incident X-ray diffraction prove that epi-semiconductor layers can be grown single crystalline with exactly the same in-plane orientation as the Si(111) substrate. Epi-Ge layers show a small fraction (less than 0.5 vol. %) of so-called type B rotation twin regions located near the oxide-Ge interface. The main structural defects for both epi materials are micro twin lamellas lying in {111} planes 70° inclined to the wafer surface that may reach through the whole layer from the oxide interface to the surface. Furthermore, TEM confirms the existence of stacking faults and threading dislocations. X-ray grazing incident diffraction and Raman measurements show that epi-Ge layers on Pr2O3 buffer are nearly fully relaxed, while epi-Si layers on Y2O3/Pr2O3 double buffer are compressive strained depending on their own thickness and the thickness of the underlying Y2O3 layer. It is demonstrated that the epi-layer quality can be improved by post-deposition annealing procedures.
Publisher: IEEE
Date: 06-2017
Publisher: American Physical Society (APS)
Date: 25-09-2014
Publisher: American Physical Society (APS)
Date: 11-12-2017
Publisher: Elsevier BV
Date: 10-2019
Publisher: IEEE
Date: 06-2017
Publisher: IEEE
Date: 07-2018
Publisher: Wiley
Date: 27-07-2009
Publisher: IEEE
Date: 06-2017
Publisher: American Physical Society (APS)
Date: 23-07-2012
Publisher: Cambridge University Press (CUP)
Date: 06-2010
DOI: 10.1154/1.3392302
Abstract: It is demonstrated that a complex X-ray characterization of semiconductor films epitaxially grown on metal oxide buffer layers and Si(111) substrates is possible using laboratory-based equipment. This is demonstrated with epi-germanium on Pr 2 O 3 as buffer material. Pole figure measurements prove that epi-Ge layers are nearly single crystalline with exactly the same in-plane orientation (type A) as the Si(111) substrate, while the lattice of the oxide layer is 180° rotated around the [111] surface normal (type B). Only a small fraction (less than 0.6 vol %) of the epi-Ge exhibits type B rotation twins. The main structural defects are microtwin lamellas lying in {111} planes 70.5° inclined to the wafer surface. The different in-plane orientation of the Si substrate and epi-Ge on one side and the Pr 2 O 3 buffer layer on the other side allows a very sensitive analysis of strain and defects even for a 10-nm oxide layer buried under a 100-nm Ge. The epi-Ge layers are nearly fully relaxed and the Pr 2 O 3 buffer layer is compressively strained. Due to the existing defects the Ge (111) planes are tilted in a characteristic pattern relative to the Si substrate.
Publisher: Elsevier BV
Date: 07-2009
Publisher: Wiley
Date: 13-09-2012
Publisher: AIP Publishing
Date: 15-04-2008
DOI: 10.1063/1.2870270
Abstract: A combined structure and stoichiometry study on the growth behavior of single crystalline Ge(111) layers on PrO2(111)∕Si(111) heterostructures is presented. Ex situ x-ray diffraction techniques indicate that the interaction between Ge and PrO2(111) results in a complete reduction of the buffer oxide to a cubic Pr2O3(111) film structure. In situ reflection high energy electron diffraction, x-ray and ultraviolet photoelectron spectroscopy studies demonstrate that this chemical reduction of the oxide support occurs during the initial Ge growth stage. The interaction of PrO2 with Ge results in the formation of an amorphous Ge oxide layer by the diffusion of lattice oxygen from the dielectric to the forming semiconductor deposit. After the complete conversion of PrO2 to cubic Pr2O3, the supply of reactive lattice oxygen is exhausted and the continuous Ge deposition reduces the initially formed amorphous GeO2-like film to GeO. The sublimation of volatile GeO uncovers the single crystalline cubic Pr2O3(111) film surface which provides a thermodynamically stable template for elemental Ge heteroepitaxy. A Volmer–Weber growth mode is observed which results after island coalescence in the formation of atomically smooth, single crystalline Ge(111) layers.
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D0NR07441A
Abstract: Coassembly between block copolymers and nanodiamonds (NDs) leads to transparent UV-protective coatings and hybrid superstructures with hierarchical assembly of NDs.
Publisher: AIP Publishing
Date: 08-2007
DOI: 10.1063/1.2767374
Abstract: The stoichiometry, structure, and defects of self-assembled heteroepitaxial Ge nanodots on twin-free type B oriented cubic Pr2O3(111) layers on Si(111) substrates are studied to shed light on the fundamental physics of nanocrystal based nonvolatile memory effects. X-ray photoelectron spectroscopy studies prove the high stoichiometric purity of the Ge nanodots on the cubic Pr2O3(111)∕Si(111) support system. Synchrotron based x-ray diffraction, including anomalous scattering techniques, was applied to determine the epitaxial relationship, showing that the heteroepitaxial Ge(111) nanodots crystallize in the cubic diamond structure with an exclusive type A stacking configuration with respect to Si(111). Grazing incidence small angle x-ray scattering was used in addition to analyze the average shape, size, and distance parameters of the single crystalline Ge nanocrystal ensemble. Furthermore, transmission electron micrographs report that partial dislocations are the prevailing extended defect structure in the Ge nanodots, mainly induced by surface roughness on the atomic scale of the cubic Pr2O3(111) support.
Publisher: AIP Publishing
Date: 10-2009
DOI: 10.1063/1.3224947
Abstract: The defect structure of Ge(111) epilayers grown by molecular beam epitaxy on cubic Pr2O3(111)/Si(111) support systems was investigated by means of transmission electron microscopy and laboratory-based x-ray diffraction techniques. Three main types of defects were identified, namely, rotation twins, microtwins, and stacking faults, and studied as a function of Ge film thickness and after annealing at 825 °C in ultrahigh vacuum. Rotation twins were found to be localized at the Ge(111)/cubic Pr2O3(111) interface and their amount could be lowered by the thermal treatment. Microtwins across {111¯} were detected only in closed Ge films, after Ge island coalescence. The fraction of Ge film volume affected by microtwinning is constant within the thickness range of ∼20–260 nm. Beyond 260 nm, the density of microtwins is clearly reduced, resulting in thick layers with a top part of higher crystalline quality. Microtwins resulted insensitive to the postdeposition annealing. Instead, the density of stacking faults across {111¯} planes decreases with the thermal treatment. In conclusion, the defect density was proved to diminish with increasing Ge thickness and after annealing. Moreover, it is noteworthy that the annealing generates a tetragonal distortion in the Ge films, which get in-plane tensely strained, probably due to thermal mismatch between Ge and Si.
Publisher: Elsevier BV
Date: 07-2008
Publisher: IEEE
Date: 2000
Publisher: IOP Publishing
Date: 06-09-2010
Publisher: American Chemical Society (ACS)
Date: 03-12-2014
DOI: 10.1021/JP507183F
Publisher: Informa UK Limited
Date: 30-10-2014
Publisher: Elsevier BV
Date: 05-2007
Publisher: AIP Publishing
Date: 15-09-2010
DOI: 10.1063/1.3485830
Abstract: The preparation of GaN virtual substrates on Si wafers via buffer layers is intensively pursued for high power/high frequency electronics as well as optoelectronics applications. Here, GaN is integrated on the Si platform by a novel engineered bilayer oxide buffer, namely, Sc2O3/Y2O3, which gradually reduces the lattice misfit of ∼−17% between GaN and Si. Single crystalline GaN(0001)/Sc2O3(111)/Y2O3(111)/Si(111) heterostructures were prepared by molecular beam epitaxy and characterized ex situ by various techniques. Laboratory-based x-ray diffraction shows that the epitaxial Sc2O3 grows fully relaxed on the Y2O3/Si(111) support, creating a high quality template for subsequent GaN overgrowth. The high structural quality of the Sc2O3 film is demonstrated by the fact that the concentration of extended planar defects in the preferred {111} slip planes is below the detection limit of synchrotron based diffuse x-ray scattering studies. Transmission electron microscopy (TEM) analysis reveal that the full relaxation of the −7% lattice misfit between the isomorphic oxides is achieved by a network of misfit dislocations at the Sc2O3/Y2O3 interface. X-ray reflectivity and TEM prove that closed epitaxial GaN layers as thin as 30 nm can be grown on these templates. Finally, the GaN thin film quality is studied using a detailed Williamson–Hall analysis.
Publisher: Springer Science and Business Media LLC
Date: 12-02-2016
DOI: 10.1038/SREP20633
Abstract: Phase-change materials based on Ge-Sb-Te alloys are widely used in industrial applications such as nonvolatile memories, but reaction pathways for crystalline-to-amorphous phase-change on picosecond timescales remain unknown. Femtosecond laser excitation and an ultrashort x-ray probe is used to show the temporal separation of electronic and thermal effects in a long-lived ( ps) transient metastable state of Ge 2 Sb 2 Te 5 with muted interatomic interaction induced by a weakening of resonant bonding. Due to a specific electronic state, the lattice undergoes a reversible nondestructive modification over a nanoscale region, remaining cold for 4 ps. An independent time-resolved x-ray absorption fine structure experiment confirms the existence of an intermediate state with disordered bonds. This newly unveiled effect allows the utilization of non-thermal ultra-fast pathways enabling artificial manipulation of the switching process, ultimately leading to a redefined speed limit and improved energy efficiency and reliability of phase-change memory technologies.
Publisher: American Physical Society (APS)
Date: 27-09-2012
Publisher: AIP Publishing
Date: 09-12-2013
DOI: 10.1063/1.4847715
Abstract: We present an angle-resolved photoemission study of a ternary phase change material, namely Ge2Sb2Te5, epitaxially grown on Si(111) in the metastable cubic phase. The observed upper bulk valence band shows a minimum at Γ¯ being 0.3 eV below the Fermi level EF and a circular Fermi contour around Γ¯ with a dispersing diameter of 0.27–0.36 Å−1. This is in agreement with density functional theory calculations of the Petrov stacking sequence in the cubic phase which exhibits a topological surface state. The topologically trivial cubic Kooi-De Hosson stacking shows a valence band maximum at Γ in line with all previous calculations of the hexagonal stable phase exhibiting the valence band maximum at Γ for a trivial Z2 topological invariant ν0 and away from Γ for non-trivial ν0. Scanning tunneling spectroscopy exhibits a band gap of 0.4 eV around EF.
Publisher: AIP Publishing
Date: 07-08-2014
DOI: 10.1063/1.4892394
Abstract: The structural change upon annealing of an amorphous GeSbTe (GST) film deposited by molecular beam epitaxy on a Si(111) substrate is studied by means of X-ray diffraction (XRD), X-ray reflectivity (XRR), and atomic force microscopy (AFM). XRD profiles reveal that both metastable cubic and stable hexagonal phases are obtained with a single out-of-plane orientation. XRR study shows a density increase and consequent thickness decrease upon annealing, in accordance with literature. From both, the XRD and the AFM study, it emerges that the crystalline substrate acts as a template for the film, favoring the crystallization of the amorphous GST into the [111] oriented metastable cubic phase, and the latter turns into the [0001] stable hexagonal phase for higher annealing temperature.
Publisher: Elsevier BV
Date: 12-2006
Publisher: IOP Publishing
Date: 13-02-2014
DOI: 10.1088/0953-8984/26/9/095802
Abstract: Quantum corrections to the conductivity due to the weak antilocalization (WAL) and electron-electron interaction (EEI) effects are investigated in Sb-Te layers to evaluate the number of independent conduction channels in the topological insulator system. We separate the two contributions in the logarithmic temperature dependence of conductivity relying on their distinct response to a magnetic field. For the WAL effect, the litude parameter α being -1 observed in magnetoconductivity is confirmed. The magnitude of the EEI contribution is too large to be produced by one transport channel. The mixing between the surface and bulk states is thus indicated to be weak in the Sb-Te system. In addition, the disorder scattering appears to be less influential for the EEI effect than for the WAL effect.
Publisher: Springer Science and Business Media LLC
Date: 17-07-2014
DOI: 10.1038/SREP05727
Publisher: Elsevier BV
Date: 08-2019
Publisher: AIP Publishing
Date: 28-03-2015
DOI: 10.1063/1.4916529
Publisher: AIP Publishing
Date: 11-05-2020
DOI: 10.1063/5.0006164
Abstract: A relation between the boundary curvature κ and the wrinkle wavelength λ of a thin suspended film under boundary confinement is demonstrated. Experiments were performed with nanocrystalline diamond films of approximate thickness 184 nm grown on glass substrates. By removing portions of the substrates after growth, suspended films with circular boundaries of radius 30–811 μm were fabricated. Due to residual stresses, the portions of the film bonded to the substrate are of approximate compressive prestrain 11×10−4 and the suspended portions of the film are azimuthally wrinkled at their boundary. Measurements show that λ decreases monotonically with κ, and a simple model that is in line with this trend is proposed. The model can be applied to design devices with functional wrinkles and can be adapted to gain insight into other systems such as plant leaves. A method for measuring residual compressive strain in thin films, which complements standard strain characterization methods, is also described.
Publisher: AIP Publishing
Date: 15-11-2010
DOI: 10.1063/1.3511751
Abstract: Crystalline oxides on Si with tailored electronic and crystallographic properties are of importance for the integration of functional oxides or alternative semiconductors to enable novel device concepts in Si microelectronics. We present an electronic band gap study of single crystalline Pr2−xYxO3 (0≤x≤2) heterostructures on Si(111). The perfect solubility of the isomorphic bixbyites Pr2O3 and Y2O3 during molecular beam epitaxy thin film growth on Si enables a linear band gap tuning. Special focus is devoted to the determination of the electronic band offsets across the dielectric/Si interface. In addition, the composition x allows to control the crystallographic lattice parameter where, for ex le, Pr0.8Y1.2O3 enables the growth of fully lattice matched oxide heterostructures on Si.
Publisher: Elsevier BV
Date: 12-2004
Publisher: AIP Publishing
Date: 21-07-2008
DOI: 10.1063/1.2958227
Abstract: A film of praseodymium sesquioxide with hexagonal structure, that has been deposited on Si(111) by molecular beam epitaxy, was annealed in oxygen atmosphere to obtain a PrO2 film for improved heteroepitaxy as buffer dielectric for alternative semiconductor layer integration. The film structure is characterized by x-ray diffraction and x-ray reflectometry. The film is single crystalline with Fm3¯m (fluorite) structure. It is B oriented with respect to Si and has lattice constants close to bulk PrO2. The cubic lattice of the PrO2 film is slightly distorted due to residual oxygen vacancies which increase the diameter of Pr ions.
Publisher: OSA
Date: 2016
Publisher: OSA
Date: 2014
Publisher: OSA
Date: 2014
Publisher: AIP Publishing
Date: 15-04-2008
DOI: 10.1063/1.2906031
Abstract: The isomorphic oxide-on-oxide epitaxy of Y2O3 on cubic Pr2O3(111)∕Si(111) support systems was studied to tailor the lattice constant of the dielectric heterostructure for future integration of functional semiconductors via heteroepitaxy on the Si material platform. Laboratory- and synchrotron-based x-ray diffraction was applied to study the structure as well as the epitaxy mechanism of Y2O3 on the cubic Pr2O3(111)∕Si(111) support. The oxide heterostructure is characterized by the formation of closed single crystalline cubic Y2O3(111) films which are in especial twin-free and exhibit an exclusive type B epitaxy orientation on the cubic Pr2O3(111)∕Si(111) system. Nondestructive depth profiling x-ray diffraction reveals that the epitaxy mechanism of Y2O3 films on cubic Pr2O3(111)∕Si(111) systems is determined by the formation of a transition layer with variable lattice parameters, changing with increasing depth from the Y2O3 values towards the parameters of the isomorphic Pr2O3 support. This transition layer thus effectively accomodates the relatively large lattice misfit of 4.8% between the isomorphic oxides. X-ray photoelectron depth profiling studies are applied to discriminate between strain and interface reaction effects in the formation of this transition region at the Y2O3∕Pr2O3 boundary. An interface reaction, forming a compositionally graded Pr2−xYxO3 (x=0–2) buffer layer at the oxide/oxide boundary, results as the most probable physical origin.
Publisher: Wiley
Date: 03-2009
Publisher: Wiley
Date: 22-10-2012
Location: No location found
Location: Japan
No related grants have been discovered for Alessandro Giussani.