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: In this article, the authors present a first principle study of the band alignment at AlN/diamond heterojunctions and show that the average valence-band offset is about 1.6 eV, corresponding to a staggered (type II) band alignment.
14 citations
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TL;DR: The observations of the unique optical properties induced by efficient charge transfer are very helpful for exploring novel TMDC-based optoelectronic devices.
Abstract: The charge-transfer process in transition-metal dichalcogenides (TMDCs) lateral homojunction affects the electron-hole recombination process of in optoelectronic devices. However, the optical properties of the homojunction reflecting the charge-transfer process has not been observed and studied. In this work, we investigated the charge-transfer-induced emission properties based on monolayer (1L)-bilayer (2L) WSe2 lateral homojunction with dozens of nanometer monolayer region. On the one hand, the photoluminescence (PL) emission of bilayer WSe2 from the homojunction area blue shifts ∼23 and ∼31 meV for direct and indirect bandgap emission, respectively, compared with the bare WSe2 bilayer region. The blue shift of the emission spectrum in the bilayer WSe2 is ascribed to the decrease in binding energy induced by charge transfer from monolayer to bilayer. On the other hand, the energy shift shows a tendency to increase as the temperature decreases. The energy blue shift is ∼57 meV for direct bandgap emission at 80 K, which is larger than that (∼23 meV) at room temperature. The larger-energy blue shift at low temperature is derived from the larger driving force under larger band offset. Our observations of the unique optical properties induced by efficient charge transfer are very helpful for exploring novel TMDC-based optoelectronic devices.
14 citations
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TL;DR: In this article, full-potential linearized augmented plane wave calculations have been performed to study the structural, electronic and magnetic properties of the Co/sub 2/MnGe Heusler compound, showing that the predicted band offset is not suitable for spin-injection and that the half-metallicity is lost in proximity to the junction.
Abstract: Within density functional theory, full-potential linearized augmented plane wave calculations have been performed to study the structural, electronic and magnetic properties of the Co/sub 2/MnGe Heusler compound. As a result of the semiconducting (metallic) character found in the minority (majority) band structure, this material is predicted to be half-metallic, with an integer magnetic moment of 5 /spl mu//sub B/. This peculiar property, highly desired for spintronics applications, stimulated the study of the Co/sub 2/MnGe/GaAs interface. Our calculations show that the predicted band offset is not suitable for spin-injection and that, due to interface states, the half-metallicity is lost in proximity to the junction.
14 citations
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TL;DR: In this paper, a review of the present understanding of band edge and free carrier properties in Hg-based superlattices such as HgTe-CdTe is presented.
Abstract: The present understanding of band edge and free carrier properties in Hg-based superlattices such as HgTe-CdTe is reviewed. The authors emphasise the relation between distinctive aspects of the superlattice band structures obtained theoretically and corresponding features in the magneto-transport, magneto-optical and optical data. Theory predicts a high sensitivity of the free carrier properties to the magnitude of the valence band offset. One finds that nearly all of the main experimental results (excepting low-temperature negative differential resistance) are qualitatively consistent with a large offset, but are difficult to explain if the offset is small. The valence band offset controversy thus appears to have been largely resolved.
14 citations
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29 Jan 2021TL;DR: In this paper, an n-type ZnO/p-type GaAs solar cell is modeled by analyzing the band edge discontinuities, electric field distributions at the interface and cell parameters with varying ZnOs layer thickness, affinity values and carrier concentration.
Abstract: Currently, how to improve the efficiency of solar cells has attracted wide attention. ZnO film is one of the most effective films today, which can act as both emitter and anti-reflective coating of solar cells. In this paper, n-type ZnO/p-type GaAs solar cell is modeled by analyzing the band edge discontinuities, electric field distributions at the ZnO/GaAs interface and cell parameters with varying ZnO layer thickness, affinity values and carrier concentration. Moreover, in order to improve the band offset alignment at the heterojunction, Mg doped ZnO emitter is a possible alternative. Then, the thickness and carrier concentration of MgZnO emitter layer are studied and simulation results show stronger electric field, better fill factor and higher efficiency. After optimization of two solar cells by using Silvaco Atlas, it is observed that the conversion efficiencies of ZnO/GaAs and MgZnO/GaAs solar cells are 22.84% and 23.44% respectively.
14 citations