Size-dependent exciton binding energy in semiconductor nanostructures

He, Yan; Hu, Sumei; Zhu, Weiling; Ouyang, Gang

doi:10.1088/1361-6463/ab5f2f

Cited by 9 publications

(10 citation statements)

References 37 publications

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“…where t j is one-electron kinetic energy, the subscript j runs for all orbitals, and ∑ j n j t j = T s (6) is the total independent-particle kinetic energy for the Kohn-Sham auxiliary system. It is not the true electronic kinetic energy of the prototype system, and a part of E XC should account for their difference.…”

Section: Formal Derivationmentioning

confidence: 99%

“…Optical absorption could generate electron-hole pairs, but they have electrostatic attraction in general. Therefore, the optical gap is usually smaller than the fundamental gap due to the finite exciton binding energy [6]. Sometimes the measured optical gap can be larger than the fundamental gap due to the optically forbidden transition [7], but that corresponds to special cases and will not be considered here.…”

Section: Introductionmentioning

confidence: 99%

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DFT-1/2 and shell DFT-1/2 methods: electronic structure calculation for semiconductors at LDA complexity

Mao

Yan

Xue

et al. 2022

J. Phys.: Condens. Matter

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It is known that the Kohn-Sham eigenvalues do not characterize experimental excitation energies directly, and the band gap of a semiconductor is typically underestimated by local density approximation (LDA) of density functional theory (DFT). An embarrassing situation is that one usually uses LDA+U for strongly correlated materials with rectified band gaps, but for non-strongly-correlated semiconductors one has to resort to expensive methods like hybrid functionals or GW. In spite of the state-of-the-art meta-GGA functionals like TB09 and SCAN, methods with LDA-level complexity to rectify the semiconductor band gaps are in high demand. DFT-1/2 stands as a feasible approach and has been more widely used in recent years. In this work we give a detailed derivation of the Slater half occupation technique, and review the assumptions made by DFT-1/2 in semiconductor band structure calculations. In particular, the self-energy potential approach is verified through mathematical derivations. The aims, features and principles of shell DFT-1/2 for covalent semiconductors are also accounted for in great detail. Other developments of DFT-1/2 including conduction band correction, DFT+A-1/2, empirical formula for the self-energy potential cutoff radius, etc., are further reviewed. The relations of DFT-1/2 to hybrid functional, sX-LDA, GW, self-interaction correction, scissor’s operator as well as DFT+U are explained. Applications, issues and limitations of DFT-1/2 are comprehensively included in this review.

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Section: Formal Derivationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

DFT-1/2 and shell DFT-1/2 methods: electronic structure calculation for semiconductors at LDA complexity

Mao

Yan

Xue

et al. 2022

J. Phys.: Condens. Matter

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“…Therefore, the physical properties of excitons in perovskite materials are an important part of the study of their luminescence process. In addition, it has also been well reported that the size of the semiconductor material significantly affects the exciton binding energy of the material, thereby affecting the light-emitting performance of the material [44]. Bastard et al calculated in detail the influence of quantum well width on exciton binding energy [45], and Elward et al found through calculations that the exciton binding energy in CdSe quantum dots decreases as the material size increases [46].…”

Section: Resultsmentioning

confidence: 99%

Two photon pumped nanowire laser based on all inorganic perovskite with high exciton binding energy grown by physical vapor deposition

Sun¹,

Wang²,

Li³

et al. 2021

J. Phys. D: Appl. Phys.

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Cesium lead halide (CsPbBr3) perovskite nanomaterials exhibit attractive optical properties, particularly in higher nonlinear optical effects and larger multiphoton absorption efficiency, compared with conventional semiconductors. The unique feature of stable lasing action under photon pumping conditions grants such materials great potential in photonics. Herein, through an in-depth study of the growing mechanism, all-inorganic perovskite nanomaterials with a high crystalline quality and tunable morphologies were synthesized, by a modified physical vapor deposition procedure. The prepared nanowire laser not only presents a high-performance laser output under single-photon pumping conditions, but also maintains decent behavior under two-photon pumping conditions. Importantly, the temperature-dependent fluorescence spectroscopy test of the nanowires reveals that the high exciton binding energy, twice as large as the thermal disturbance at room temperature, is the dominant reason for maintaining stable lasing under high energy density injection conditions.

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“…[71] As an important part of many materials such as composite materials and heterojunction structures, interface plays a very important role in the performance regulation, so it has attracted attention of many scholars. [72][73][74][75] Specific to the field of crystalline-amorphous interface, the importance of the interface is mainly reflected in the mechanical properties of the structure, especially the plastic deformation ability. Wang et al [15] prepared the Cu/CuZr crystalline/amorphous multilayers and agree that the amorphous-crystal interfaces exhibit unique inelastic shear (slip) transfer characteristics, fundamentally different from those of grain boundaries.…”

Section: Plastic Deformation Mechanism In Amorphous Phasementioning

confidence: 99%

Layer thickness dependent plastic deformation mechanism in Ti/TiCu dual-phase nano-laminates

et al. 2023

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Crystalline/amorphous nanolaminate is an effective strategy to improve the mechanical properties of metallic materials, but the underlying deformation mechanism is still under the way of exploring. Here, the mechanical properties and plastic deformation mechanism of Ti/TiCu dual-phase nanolaminates (DPNLs) with different layer thickness are investigated using molecular dynamics simulations. The results indicate that the influence of the layer thickness on the plastic deformation mechanism in crystalline layer is negligible, while it affects the plastic deformation mechanism of amorphous layers distinctly. The crystallization of amorphous TiCu is exhibited in amorphous parts of the Ti/TiCu DPNLs, which is inversely proportional to the layer thickness. It is observed that the crystallization of the amorphous TiCu is a process driven by stress and heat. The Young’s modulus for the Ti/TiCu DPNLs are higher than that of composite material due to the amorphous/crystalline interfaces. Furthermore, the main plastic deformation mechanism in crystalline part: grain reorientation, transformation from hexagonal-close-packed-Ti to face-centered cubic-Ti and body-centered cubic-Ti, has also been displayed in present work. The results may provide a guideline for the design of high-performance Ti and its alloy.

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Size-dependent exciton binding energy in semiconductor nanostructures

Cited by 9 publications

References 37 publications

DFT-1/2 and shell DFT-1/2 methods: electronic structure calculation for semiconductors at LDA complexity

DFT-1/2 and shell DFT-1/2 methods: electronic structure calculation for semiconductors at LDA complexity

Two photon pumped nanowire laser based on all inorganic perovskite with high exciton binding energy grown by physical vapor deposition

Layer thickness dependent plastic deformation mechanism in Ti/TiCu dual-phase nano-laminates

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