scispace - formally typeset
Search or ask a question
Topic

Band offset

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


Papers
More filters
Proceedings ArticleDOI
07 Dec 1997
TL;DR: The origin of electron traps, which induce leakage currents in SiO/sub 2/ films, is predicted to be an oxygen (O) vacancy from first-principles total energy calculations.
Abstract: The origin of electron traps, which induce leakage currents in SiO/sub 2/ films, is predicted to be an oxygen (O) vacancy from first-principles total-energy calculations. Once a neutral O vacancy traps holes, it spontaneously changes to a large distorted structure. The distorted O vacancy can capture electrons, and remains as an electron trap in SiO/sub 2/ films. These results give a microscopic explanation for a trap model that is empirically deduced from experiments. The energy level of the generated electron trap exists near the band offset between the conduction band of SiO/sub 2/ and that of Si. From these results, the electron trap originating from a hole trapped O vacancy can be considered as one origin of the so-called stress-induced leakage currents in SiO/sub 2/ films.

39 citations

Journal ArticleDOI
TL;DR: In this paper, the authors employed a soft-X-ray ARPES technique, using synchrotron radiation with photon energies around 1 keV, to probe the electronic structure of the buried EuO/Si interface with momentum resolution and chemical specificity.
Abstract: Semiconductor spintronics provides a framework for hybrid devices combining logic, communication and storage, circumventing limitations of the current electronics, especially with respect to the energy efficiency. Enormous efforts have been invested worldwide into the development of spintronics based on Si, the mainstream semiconductor platform. Notwithstanding remarkable pace, Si spintronics still experiences a technological bottleneck – creation of significant spin polarization in nonmagnetic Si. An emerging approach based on direct electrical spin injection from a ferromagnetic semiconductor – EuO being the prime choice – avoids problems inherent to metallic injectors. The functionality of the EuO/Si spin contact is controlled by the interface band alignment. To be competitive with charge electronics, the EuO/Si interface should exhibit a band offset which falls within the 0.5–2 eV range. We employ a soft-X-ray ARPES technique, using synchrotron radiation with photon energies around 1 keV, to probe the electronic structure of the buried EuO/Si interface with momentum resolution and chemical specificity. The band structure reveals a conduction band offset of 1.0 eV attesting the technological potential of the EuO/Si system.

38 citations

Journal ArticleDOI
TL;DR: In this article, structural, morphological, and band offset properties of GaAs/Ge/GaAs heterostructures grown in situ on (100), (110), and (111)A GaAs substrates using two separate molecular beam epitaxy chambers, connected via vacuum transfer chamber, were investigated.
Abstract: Structural, morphological, and band offset properties of GaAs/Ge/GaAs heterostructures grown in situ on (100), (110), and (111)A GaAs substrates using two separate molecular beam epitaxy chambers, connected via vacuum transfer chamber, were investigated. Reflection high energy electron diffraction (RHEED) studies in all cases exhibited a streaky reconstructed surface pattern for Ge. Sharp RHEED patterns from the surface of GaAs on epitaxial Ge/(111)A GaAs and Ge/(110)GaAs demonstrated a superior interface quality than on Ge/(100)GaAs. Atomic force microscopy reveals smooth and uniform morphology with surface roughness of Ge about 0.2–0.3 nm. High-resolution triple axis x-ray rocking curves demonstrate a high-quality Ge epitaxial layer as well as GaAs/Ge/GaAs heterostructures by observing Pendellosung oscillations. Valence band offset, ΔEv, have been derived from x-ray photoelectron spectroscopy (XPS) data on GaAs/Ge/GaAs interfaces for three crystallographic orientations. The ΔEv values for epitaxial GaAs...

38 citations

Journal ArticleDOI
TL;DR: In this paper, the Stranski-Krastanow growth mode was used for the growth of self-assembled InP quantum dots on GaInP by low-pressure metal-organic vapor phase epitaxy (MOVPE).
Abstract: In order to achieve laser emission in the visible part of the spectrum, we have investigated the growth of self-assembled InP quantum dots on GaInP by low-pressure metal-organic vapor phase epitaxy (MOVPE) using the Stranski-Krastanow growth mode. Unlike the well-established InAs-GaAs system, when InP is deposited on GaInP, typically, two types of coherently strained islands with different sizes are formed. A high density of small islands is favored when using growth conditions with a reduced surface diffusion, i.e., low temperatures, high growth rates, and substrates with high misorientation angles. After the deposition of 3.4 monolayers of InP at 580/spl deg/C on GaAs-substrates with a surface angle of 15/spl deg/ to the next [111]B-plane, 2.10/sup 10/ InP dots per square centimeter with an average height of 4 nm were assembled. The emission of these InP islands at 1.72 eV (4.2 K) shows an inhomogeneous broadening of 42 meV because of the size fluctuation of the quantum dots. At 90 K, lasing from self-assembled InP quantum islands was observed above a threshold current density of 288 A/cm/sup 2/. The detected laser line is located at 1.8 eV, about 80 meV higher than is the ground-state transition energy. We attribute this behavior to lasing from excited states in agreement with power-dependent photoluminescence experiments. For temperatures above 150 K, the threshold current density increases dramatically because of a thermally activated escape of carriers up to 4.9 k17/cm/sup 2/ at room temperature, where the characteristic temperature is 35 K. Injection lasers containing stacked InP quantum islands and AlGaInP barrier layers with a higher band offset may exhibit an improved temperature dependence.

38 citations

Journal ArticleDOI
TL;DR: The appropriate bandgap, suitable band edge positions, and effective carrier separation make the h-BN/C2N HS a promising candidate for use as a photocatalyst in water-splitting.
Abstract: The construction of a heterostructure (HS) is an effective strategy to modulate the desired properties of two-dimensional (2D) materials and to extend their applications. In this paper, based on the density functional theory, we predict a metal-free type-II HS formed by h-BN and C2N single layers. The h-BN/C2N HS possesses a smaller bandgap than individual h-BN and C2N single layers, and it exhibits excellent visible light absorption. Importantly, its band edge positions satisfy the requirements for spontaneous water-splitting. With the assistance of the built-in electric field across the HS and the band offset, the photoinduced carriers can be readily spatially separated. Free energy calculations indicate the high catalytic activity for water oxidation and reduction reactions. The performance can be further enhanced by strain, which modulates the bandgap and the band edge positions of the HS. The band alignment may undergo a transition from type-I to type-II under strain, offering an effective switch for the reaction. The appropriate bandgap, suitable band edge positions, and effective carrier separation make the h-BN/C2N HS a promising candidate for use as a photocatalyst in water-splitting.

38 citations


Network Information
Related Topics (5)
Band gap
86.8K papers, 2.2M citations
91% related
Thin film
275.5K papers, 4.5M citations
90% related
Silicon
196K papers, 3M citations
89% related
Amorphous solid
117K papers, 2.2M citations
85% related
Raman spectroscopy
122.6K papers, 2.8M citations
82% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202336
202267
202178
202085
201980
201882