InxGa1± xP/GaAs (x ˆ 0.541 and 0.427) heterostructures, grown by Atomic Layer Molecular Beam Epitaxy (ALMBE) on low temperature substrates, have been characterised by pressure-dependent and time-resolved photoluminescence experiments. The excitonic optical transitions and recombination dynamics are both influenced by the particular band alignments of these systems. The valence band offset has b...

We measured valence band offsets in Ta2O5–WO3, Ta2O5–Nb2O5 and WO3–Nb2O5 heterostructure couples by in situ x-ray photoelectron spectroscopy, immediately following the bi-layer growth in ultra-high vacuum. Conduction band offsets were estimated using the measured valence band offsets in conjunction with the literature values for the respective band gaps. The offsets between Ta2O5 and WO3 and be...

CdSe is used as a prototype to show the implications of valence-band degeneracy for the optical properties of strongly quantum-confined nanocrystals. Absorption spectra and photoluminescence spectra obtained under intermediate and strong pulsed excitation show the presence of new structures. The energy levels for the electron and the hole are calculated with the spherical confinement, the nonpa...

The origin of high hole conduction in BaCuQF Q=S,Se was investigated by photoemission measurements and full-potential linearized augmented plane wave band-structure calculations. In both compounds, the large dispersion near the top of the valence band is realized by admixed states of Cu 3d and S 3p or Se 4p orbitals, indicating that high hole mobility is possible. In addition, the valence band ...

The electronic structures of BiOX (X = F, Cl, Br, I) photocatalysts have been calculated with and without Bi 5d states using the experimental lattice parameters, via the plane-wave pseudopotential method based on density functional theory (DFT). BiOF exhibits a direct band gap of 3.22 or 3.12 eV corresponding to the adoption of Bi 5d states or not. The indirect band gaps of BiOCl, BiOBr, and Bi...

Abstract The spectral momentum densities of vanadium metal and V2O3 are measured by electron momentum spectroscopy. Results are compared with band structure calculations based on density functional theory (DFT). Qualitatively, the agreement between theory and experiment is good. The calculated total band width of vanadium metal (6.5 eV) is in excellent agreement with the observed one (6.5 ± 0.2...

X-ray photoelectron spectroscopy has been used to measure the valence band offset of the InN/BaTiO3 heterojunction. It is found that a type-I band alignment forms at the interface. The valence band offset (VBO) and conduction band offset (CBO) are determined to be 2.25 ± 0.09 and 0.15 ± 0.09 eV, respectively. The experimental VBO data is well consistent with the value that comes from transitivi...

A detailed study on the mechanism of band-to-band tunneling in carbon nanotube field-effect transistors (CNFETs) is presented. Through a dual-gated CNFET structure tunneling currents from the valence into the conduction band and vice versa can be enabled or disabled by changing the gate potential. Different from a conventional device where the Fermi distribution ultimately limits the gate volta...