Topic
Band offset
About: Band offset is a research topic. Over the lifetime, 2446 publications have been published within this topic receiving 53450 citations.
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TL;DR: This work uses electron transport to characterize monolayer graphene-multilayer MoS2 heterostructures and is able to interpret their measurements quantitatively by accounting for disorder and using the random phase approximation for the exchange and correlation energies of both Dirac and parabolic-band two-dimensional electron gases.
Abstract: We use electron transport to characterize monolayer graphene - multilayer MoS2 heterostructures. Our samples show ambipolar characteristics and conductivity saturation on the electron branch which signals the onset of MoS2 conduction band population. Surprisingly, the carrier density in graphene decreases with gate bias once MoS2 is populated, demonstrating negative compressibility in MoS2. We are able to interpret our measurements quantitatively by accounting for disorder and using the random phase approximation (RPA) for the exchange and correlation energies of both Dirac and parabolic-band two-dimensional electron gases. This interpretation allows us to extract the energetic offset between the conduction band edge of MoS2 and the Dirac point of graphene.
105 citations
TL;DR: In this article, the Schottky barrier heights and band offsets of metal oxide semiconductor interfaces have been analyzed, and metal induced gap states (MIGS) have been used to give a good description of these interfaces.
105 citations
TL;DR: In this article, a variational theory is developed for excitons, especially accounting for the possibility of a small valence-band offset, and a band offset of 25 meV is deduced for the heavy-hole valence band, corresponding to a conduction-to-valence band offset ratio of about 14:1.
Abstract: The question of band offsets and details of exciton binding are investigated in the CdTe/(Cd,Mn)Te heterostructure in the quantum-well limit. Photoluminescence excitation spectroscopy in external magnetic fields is used to vary the quantum-well potential depths in this moderately strained (0.6% lattice mismatch) diluted magnetic semiconductor heterostructure. Large Zeeman splittings are observed at all the principal quantum-well transitions and at the barrier band gap for a structure of CdTe well thicknesses of 50 A\r{} and a Mn-ion concentration in the barrier layer of x=0.24. A variational theory is developed for excitons, especially accounting for the possibility of a small valence-band offset. Good agreement between theory and experiment is obtained and a band offset of 25 meV is deduced for the heavy-hole valence band, corresponding to a conduction- to valence-band offset ratio of about 14:1. This implies that the valence-band offset in a hypothetical strain-free case is virtually zero. The accuracy of the offset determination is believed to be better than 10 meV. Exciton binding energies are found to vary appreciably in the magnetic field; the zero-field value is approximately twice that for bulk CdTe.
103 citations
TL;DR: In this paper, the authors analyzed the effect of strain on the valence subband of GaxIn1−xAs/InP single-quantum-well structures using the model solid theory of Van de Walle and Martin.
Abstract: Single‐quantum‐well structures were grown by atmospheric pressure organometallic vapor‐phase epitaxy, with GaxIn1−xAs layers (0≤x≤1) coherently strained to match the lattice parameter of the InP barrier layers in the (100) growth plane. The strain effects on the band lineups were analyzed using the ‘‘model solid’’ theory of Van de Walle and Martin. The hydrostatic strain component for alloys with x≊1 is shown to be sufficient to marginally convert the type‐II lineups for the unstrained case to type I. The band lineups remain type I for x≊0. Considering the effect of strain, the ‖ (3)/(2) , (1)/(2) 〉 valence subband becomes a slowly varying function of x. Band offsets are predicted over the entire alloy composition and compared with the reported data. The photoluminescence (10 K) peak energies for the 100‐A GaxIn1−xAs/InP single quantum wells compare quite favorably with the calculated strained band gap versus x. For nominal monolayer quantum wells, the peak energies are slightly above 1.1 eV over the enti...
103 citations
TL;DR: A sample of the β-Ga2O3/wurtzite GaN heterostructure has been grown by dry thermal oxidation of GaN on a sapphire substrate and it is demonstrated that the valence band of theβ-Ga3/GaN structure is 1.40 ± 0.08 eV.
Abstract: A sample of the β-Ga2O3/wurtzite GaN heterostructure has been grown by dry thermal oxidation of GaN on a sapphire substrate. X-ray diffraction measurements show that the β-Ga2O3 layer was formed epitaxially on GaN. The valence band offset of the β-Ga2O3/wurtzite GaN heterostructure is measured by X-ray photoelectron spectroscopy. It is demonstrated that the valence band of the β-Ga2O3/GaN structure is 1.40 ± 0.08 eV.
101 citations