The ${E}_{0}$, ${E}_{0}+{\ensuremath{\Delta}}_{0}$, ${E}_{1}$, ${E}_{1}+{\ensuremath{\Delta}}_{1}$, ${E}_{0}^{\ensuremath{'}}$, and ${E}_{2}$ optical transitions have been measured in ${\mathrm{Ge}}_{1\ensuremath{-}y}{\mathrm{Sn}}_{y}$ alloys $(y<0.2)$ using spectroscopic ellipsometry photoreflectance. results indicate a strong nonlinearity (bowing) the compositional dependence of these quantities. Such behavior is not predicted by electronic structure calculations within virtual crystal...

Strain compensation is an important aspect of heterostructure engineering. In this letter, we discuss the synthesis pseudomorphic Si1−yCy and Si1−x−yGexCy alloy layers on a silicon (100) substrate by molecular beam epitaxy using solid sources controlled strain that results from introduction ternary system. The C into substitutional sites in crystal lattice kinetically stabilized low-temperature growth conditions (400–550 °C) against thermodynamically favored silicon-carbide phases. constant...

We describe a class of Si-based semiconductors in the Ge1−xSnx system. Deuterium-stabilized Sn hydrides provide low-temperature route to broad range highly metastable compositions and structures. Perfectly epitaxial diamond-cubic alloys are grown directly on Si(100) exhibit high thermal stability, superior crystallinity, crystallographic optical properties, such as adjustable band gaps lattice constants. These properties completely characterized by Rutherford backscattering, low-energy...

We study the vibrational spectrum of AlN grown on Si(111). The was deposited using gas-source molecular beam epitaxy. Raman backscattering along growth c axis and from a cleaved surface perpendicular to wurtzite direction allows us determine ${E}_{2}^{1},$ ${E}_{2}^{2},$ ${A}_{1}(\mathrm{TO}),$ ${A}_{1}(\mathrm{LO}),$ ${E}_{1}(\mathrm{TO})$ phonon energies. For 0.8-\ensuremath{\mu}m-thick layer under biaxial tensile stress 0.6 GPa, these are 249.0, 653.6, 607.3, 884.5, 666.5...

In the present study, we combine theoretical and experimental approaches in order to gain insight into electronic properties of both high-temperature, rutile (metallic) low-temperature, body-centered tetragonal (insulating) phase niobium dioxide (NbO2) as well optical low-temperature phase. Theoretical calculations performed at level local density approximation, Hubbard U correction, hybrid functional are complemented with spectroscopic ellipsometry (SE) epitaxial films grown by molecular...

We have measured the dielectric function of bulk nitrogen-doped 4H and 6H SiC substrates from 700 to 4000 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ using Fourier-transform infrared spectroscopic ellipsometry. Photon absorption by transverse optical phonons produces a strong reststrahlen band between 797 1000 with effects phonon anisotropy being observed in region longitudinal energy (960 100 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$). The shape this is influenced plasma oscillations free...

The ‘‘rigid-pseudoion’’ model is applied to intervalley scattering processes in GaAs. deformation potentials (IDPs) that we obtain at high-symmetry points are good agreement with previous calculations. We find the IDPs show a strong dependence on wave vector of phonon, therefore numerical integration over Brillouin zone (e.g., tetrahedron method) necessary realistic rates can be compared those obtained from experiments. calculate lifetimes electrons L and X valleys as function temperature...

Thermal GeO2 oxides up to 136 nm thickness were produced by annealing Ge wafers in pure oxygen at 550 °C and 270 kPa pressure for 10 h. The oxidation kinetics followed the Deal–Grove law. Using multisample spectroscopic ellipsometry a series of five thermal with different thicknesses, complex dielectric functions determined from 0.5 6.6 eV, thin-film metrology applications Ge-based microelectronics photonics. dispersion layer was modeled simple Tauc-Lorentz oscillator model, but more...

Analytical models with eight parameters have been found which describe the dielectric functions of native or electrochemically grown oxide layers on compound semiconductors GaP, GaAs, GaSb, InP, InAs, and InSb in 1.6 to 5.6 eV photon energy range. These model agree experimental optical constants within accuracy measurements. They will be useful for design analysis semiconductor laser structures, solar cells, other electro-optical devices.

We have studied the optical properties (complex dielectric function) of bulk SrTiO3 and thin films on Si Pt using spectroscopic ellipsometry over a very broad spectral range, starting at 0.03 eV [using Fourier transform infrared (FTIR) ellipsometry] to 8.7 eV. In crystals, we analyze interband transitions in spectra determine critical-point parameters. To interpret these transitions, performed band structure calculations based ab initio pseudopotentials within local-density approximation....

We calculate the isotope and temperature shifts of indirect direct band gaps in natural silicon (M\ifmmode\bar\else\textasciimacron\fi{}=28.09 u), diamond $^{12}\mathrm{C}$ its $^{13}\mathrm{C}$, germanium (M\ifmmode\bar\else\textasciimacron\fi{}=72.59 $^{70}\mathrm{Ge}$, mixture $^{75.7}\mathrm{Ge}$, due to deformation-potential-type electron-phonon interaction (within pseudopotential-bond-charge-model framework). compare these results existing experimental information data obtained by us...

We report Raman studies of the Si–Si phonon band in Si1−xGex alloys, where excitation is by visible and ultraviolet (351 nm) light. At a wavelength 351 nm, optical penetration depth extremely shallow (≈5 nm). By varying from to 514 spans 5 300 nm. Two sets samples were examined. Thin layers grown using molecular beam epitaxy coherently strained match lattice constant silicon substrate. Thick organo–metallic chemical vapor deposition strain relaxed. For thin, layers, produces spectrum, which...

We have used spectroscopic ellipsometry to measure the dielectric function \ensuremath{\epsilon}(\ensuremath{\omega}) of GaSb from 10 740 K in 1.4--5.6 eV photon-energy region. By performing a line-shape analysis observed structures, interband critical-point parameters (strength, threshold energy, broadening, and excitonic phase angle) their temperature dependence been determined. The decrease energy after correction for effect thermal expansion corresponding increase broadening with...

The intervalley electron-phonon deformation potentials between the lowest Γ−, X- and L-conduction band valleys in zinc blende semiconductors are calculated using empirical pseudopotentials for electrons realistic shell models phonons. scattering rates computed these agreement with experiments.

The structural, optical, and room-temperature electrical properties of strained La-doped SrTiO3 epitaxial thin films are investigated. Conductive with concentration varying from 5 to 25% grown by molecular beam epitaxy on four different substrates: LaAlO3, (LaAlO3)0.3(Sr2AlTaO6)0.7, SrTiO3, DyScO3, which result in lattice mismatch strain ranging −2.9% +1.1%. We compare the effect La structural optical properties, measure their resistivity mobility at room temperature. Room temperature...

Spectroscopic rotating-analyzer ellipsometry employing a compensator and optical transmission were used to measure the dielectric functions of bulk 4H 6H SiC from 0.72 6.6 eV for light propagating nearly parallel hexagonal axis. The measurements below band gap show presence thin surface layer, which was modeled as SiO2. data are similar results cubic (3C) literature, but differences notable, particularly above 4 eV. At 5.56 eV, we observe critical point in SiC, is assigned direct interband...

Single-phase SixSnyGe1−x−y alloys (x⩽0.25,y⩽0.11) were grown on Si using chemical vapor deposition. First principles simulations predict that these materials are thermodynamically accessible and yield lattice constants as a function of Si/Sn concentrations in good agreement with experiment. An empirical model derived from experimental SixGe1−x SnyGe1−y binary data also provides quantitative description the composition dependence parameters. Spectroscopic ellipsometry selected samples yields...

We have used spectroscopic ellipsometry to measure the dielectric function \ensuremath{\epsilon}(\ensuremath{\omega}) of GaP from 10 640 K in 1.6--5.6-eV photon-energy region. By performing a line-shape analysis observed structures, interband critical-point (CP) parameters (strength, threshold energy, broadening, and excitonic phase angle) their temperature dependence been determined. Special emphasis is put on ${\mathrm{E}}_{0}^{\ensuremath{'}}$,...

The impact of 8-to45-at.% Ti on physical and electrical characteristics atomic-layer-deposited annealed hafnium dioxide was studied using vacuum-ultraviolet spectroscopic ellipsometry, secondary ion mass spectroscopy, transmission electron microscopy, atomic force x-ray diffraction, Rutherford backscattering photoelectron reflectometry. role addition the performance is investigated molybdenum (Mo)-gated capacitors. film density decreases with increasing addition. stabilizes amorphous phase...

We have prepared AlSb substrates for optical measurements by chemomechanical polishing and etching. The quality of the surface was investigated with electron microscopy Raman scattering ellipsometry. measured pseudodielectric function 〈ε〉(ω) in 1.4–5.8 eV photon-energy region a spectroscopic ellipsometer. A peak value 〈ε2〉=24.6 at 4 reached. list refractive index, reflectivity, absorption coefficient, obtain critical point parameters 300 K. Finally, we fit index refraction low photon...

Many linked processes occur concurrently in strongly excited semiconductors, such as interband and intraband absorption, scattering of electrons holes by the heated lattice, Pauli blocking, bandgap renormalization formation Mahan excitons. In this work, we disentangle their dynamics contributions to optical response a ZnO thin film. Using broadband pump-probe ellipsometry, can directly unambiguously obtain real imaginary part transient dielectric function which compare with first-principles...

Hexagonal AlN layers were grown on Si(111) by gas-source molecular-beam epitaxy with ammonia. The transition between the (7×7) and (1×1) silicon surface reconstructions, at 1100 K, was used for in situ calibration of substrate temperature. initial deposition Al, 1130–1190 produced an effective nucleation layer growth AlN. Al also reduced islands SiNx that might be formed due to background NH3 prior onset epitaxial growth. two-dimensional mode, under optimum conditions, obtained after thickness ∼7 nm.

X-ray absorption spectroscopy (XAS) is used to study band edge electronic structure of high-/spl kappa/ transition metal (TM) and trivalent lanthanide rare earth (RE) oxide gate dielectrics. The lowest conduction d/sup */-states in TiO/sub 2/, ZrO/sub 2/ HfO/sub are correlated with: 1) features the O K/sub 1/ edge, 2) transitions from occupied Ti 2p, Zr 3p Hf 4p states empty 3d-, 4d-, 5d-states, respectively. relative energies d-state indicate that respective optical bandgaps, E/sub opt/ (or...

We describe methodologies for integration of compound semiconductors with Si via buffer layers and templates based on the GeSn system. These exhibit atomically flat surface morphologies, low defect densities, tunable thermal expansion coefficients, unique ductile properties, which enable them to readily absorb differential stresses produced by mismatched overlayers. They also provide a continuous selection lattice parameters higher than that Ge, allows matching technologically useful III-V...