Band offset

About: Band offset is a research topic. Over the lifetime, 2446 publications have been published within this topic receiving 53450 citations.

Analysis of Band Offset in GaNAs/GaAs by X-Ray Photoelectron Spectroscopy

Abstract: We used X-ray photoelectron spectroscopy (XPS) to measure the energy discontinuity in the valence band (ΔEv) of Ga1-xNxAs/AlAs (x=0, 0.014, 0.034) and estimated ΔEv of GaNAs/GaAs by using the Al2p energy level as a reference. The change in ΔEv for GaNAs/GaAs with an increasing nitrogen content was -(0.019±0.053) eV/%N. This suggests that the valence-band edge (Ev) in GaNAs decreases in proportion to the nitrogen content. Based on the decrease in the bandgap energy of GaNAs, we found that the energy discontinuity in the conduction band (ΔEc) of GaNAs/GaAs is -(0.175±0.053) eV/%N. This large effect of bandgap bowing on the conduction band indicates that an ideal carrier confinement in the well can be obtained by using GaInNAs as an active layer in long-wavelength laser diodes.

Staggered band alignments in AlGaAs heterojunctions and the determination of valence‐band offsets

Abstract: Photoluminescence spectra from Al0.37Ga0.63As/AlAs multiple quantum well structures with staggered band alignments are presented which provide the first direct optical measure of the valence‐band offset at a semiconductor heterojunction. The experiment takes advantage of the crossover occurring at a critical aluminum concentration above which the indirect X minima in the AlAs become the lowest energy conduction bands in the system, and recombination occurs across the interface. The resulting emission fixes the valence‐band offset at ΔEv =342±4 meV for this structure.

Tuning band offsets at semiconductor interfaces by intralayer deposition

Abstract: Etude theorique de la modification des discontinuites de bande par depot d'intracouches Si et Ge aux homojonctions GaAs et AlAs et aux heterojonctions GaAs/AlAs. La discontinuite se revele tres sensible au recouvrement et a l'aspect abrupt de l'intracouche

Effects of the layer thickness on the electronic character in GaAs‐AlAs superlattices

Abstract: Realistic tight‐binding calculations for the GaAs‐AlAs superlattice clearly demonstrate that if the GaAs layer thickness is less than ∼30 A, the lowest conduction‐band state is confined to the AlAs barrier region instead of the GaAs quantum well region resulting in a spatial separation of electrons and holes. This observation exemplifies a failure of the widely used Kronig–Penney model and emphasizes the importance of the k vector selection rule. This property can be used in photoluminescence spectroscopy to determine the band offset of thin layer superlattices for an essentially arbitrary composition of AlxGa1−xAs. A complete two‐dimensional map of the electronic character as a function of the GaAs and the AlAs layer thickness is obtained. The possibility that Xxy states may lie below Xz states for narrow wells is proposed, and implications of the present calculation on interpreting spectroscopic data are discussed.

Demonstration of high-responsivity epitaxial β-Ga2O3/GaN metal–heterojunction-metal broadband UV-A/UV-C detector

Abstract: We demonstrate epitaxial β-Ga2O3/GaN-based vertical metal–heterojunction-metal (MHM) broadband UV-A/UV-C photodetectors with high responsivity (3.7 A/W) at 256 and 365 nm, UV-to-visible rejection >103, and a photo-to-dark current ratio of ~100. A small (large) conduction (valence) band offset at the heterojunction of pulsed laser deposition (PLD)-grown β-Ga2O3 on metal organic chemical vapor deposition (MOCVD)-grown GaN-on-silicon with epitaxial registry, as confirmed by X-ray diffraction (XRD) azimuthal scanning, is exploited to realize detectors with an asymmetric photoresponse and is explained with one-dimensional (1D) band diagram simulations. The demonstrated novel vertical MHM detectors on silicon are fully scalable and promising for enabling focal plane arrays for broadband ultraviolet sensing.