Strain-engineered artificial atom as a broad-spectrum solar energy funnel

Feng, Ji; Qian, Xiaofeng; Huang, Cheng-Wei; Li, Ju

doi:10.1038/nphoton.2012.285

Cited by 988 publications

(1,017 citation statements)

References 48 publications

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“…Increase in the in-plane lattice constant by ∆a leads to reduction of direct and indirect transition energies at a different rate (Figure 2a and d) in agreement with the previous studies 16,18,19,24,30,31 . The changes are more pronounced for transitions involving the K point.…”

Section: Resultssupporting

confidence: 92%

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Origin of Indirect Optical Transitions in Few-Layer MoS₂, WS₂, and WSe₂

et al. 2013

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It has been well established that single layer MX 2 (M=Mo,W and X=S,Se) are direct gap semiconductors with band edges coinciding at the K point in contrast to their indirect gap multilayer counterparts. In few-layer MX 2 , there are two valleys along the Γ-K line with similar energy. There is little understanding on which of the two valleys forms the conduction band minimum (CBM) in this thickness regime. We investigate the conduction band valley structure in

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Section: Resultssupporting

confidence: 92%

“…In few-layer MX 2 , the conduction band valleys of the K and Λ points compete in energy. For bilayer MoS 2 and WS 2 , some calculations 16,17,21,22,24 show that the CBM is located at the K point while others 7,16,17,20 show that it is at the Λ point. The discrepancy is partly due to the fact that some calculations neglect spin-orbit interactions.…”

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Origin of Indirect Optical Transitions in Few-Layer MoS₂, WS₂, and WSe₂

et al. 2013

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“…As inorganic analogues of graphene, single-layer transition metal dichalcogenides MX 2 (M=Mo,W; X=S,Se) have an intrinsic band gap of 1.4 to 2.0 eV and are superior to graphene in certain respects [29][30][31][32][33][34][35]. Unlike graphene, the 2D MX 2 family has metal-ligand bonding and a three-atom thickness, with the M atoms sandwiched between layers of X ligands in a trigonal prismatic geometry.…”

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Intrinsic Magnetism of Grain Boundaries in Two-Dimensional Metal Dichalcogenides

et al. 2013

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Grain boundaries (GBs) are structural imperfections that typically degrade the performance of materials. Here we show that dislocations and GBs in two-dimensional (2D) metal dichalcogenides MX 2 (M = Mo, W; X = S, Se) can actually improve the material by giving it a qualitatively new physical property: magnetism. The dislocations studied all have a substantial magnetic moment of ~1 Bohr magneton. In contrast, dislocations in other well-studied 2D materials are typically non-magnetic. GBs composed of pentagon-heptagon pairs interact ferromagnetically and transition from semiconductor to half-metal or metal as a function of tilt angle and/or doping level. When the tilt angle exceeds 47° the structural energetics favor square-octagon pairs and the GB becomes an antiferromagnetic semiconductor. These exceptional magnetic properties arise from an interplay of dislocation-induced localized states, doping, and locally unbalanced stoichiometry. Purposeful engineering of topological GBs may be able to convert MX 2 into a promising 2D magnetic semiconductor.

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“…13,14 Because the elastic strain effects are greatly magnified at the micro/nanoscale, it is possible to significantly tune their properties by elastic deformation, staying away from inelastic relaxation via plasticity or rupture. 7 Recently, major progress has been achieved on elastic strain engineered semiconductor micro/nanostructures. For instance, remarkable red energy shifts of the near-band-edge (NBE) luminescence have been observed in uniaxially strained GaAs 15 and ZnO 16 nanowires, as well as in bent ZnO 17À21 and CdS 22,23 micro/nanowires through photoluminescence (PL) or cathodoluminescence (CL).…”

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Exciton Drift in Semiconductors under Uniform Strain Gradients: Application to Bent ZnO Microwires

Jacopin

Shahmohammadi

et al. 2014

ACS Nano

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Optimizing the electronic structures and carrier dynamics in semiconductors at atomic scale is an essential issue for innovative device applications. Besides the traditional chemical doping and the use of homo/heterostructures, elastic strain has been proposed as a promising possibility. Here, we report on the direct observation of the dynamics of exciton transport in a ZnO microwire under pure elastic bending deformation, by using cathodoluminescence with high temporal, spatial, and energy resolutions. We demonstrate that excitons can be effectively drifted by the strain gradient in inhomogeneous strain fields. Our observations are well reproduced by a drift-diffusion model taking into account the strain gradient and allow us to deduce an exciton mobility of 1400 ( 100 cm 2 /(eV s) in the ZnO wire. These results propose a way to tune the exciton dynamics in semiconductors and imply the possible role of strain gradient in optoelectronic and sensing nano/microdevices.

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Strain-engineered artificial atom as a broad-spectrum solar energy funnel

Cited by 988 publications

References 48 publications

Origin of Indirect Optical Transitions in Few-Layer MoS₂, WS₂, and WSe₂

Origin of Indirect Optical Transitions in Few-Layer MoS₂, WS₂, and WSe₂

Intrinsic Magnetism of Grain Boundaries in Two-Dimensional Metal Dichalcogenides

Exciton Drift in Semiconductors under Uniform Strain Gradients: Application to Bent ZnO Microwires

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Strain-engineered artificial atom as a broad-spectrum solar energy funnel

Cited by 988 publications

References 48 publications

Origin of Indirect Optical Transitions in Few-Layer MoS2, WS2, and WSe2

Origin of Indirect Optical Transitions in Few-Layer MoS2, WS2, and WSe2

Intrinsic Magnetism of Grain Boundaries in Two-Dimensional Metal Dichalcogenides

Exciton Drift in Semiconductors under Uniform Strain Gradients: Application to Bent ZnO Microwires

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Origin of Indirect Optical Transitions in Few-Layer MoS₂, WS₂, and WSe₂

Origin of Indirect Optical Transitions in Few-Layer MoS₂, WS₂, and WSe₂