Optical Properties of Bound and Localized Excitons and of Defect States

doi:10.1007/3-540-26846-4_14

Cited by 2 publications

(2 citation statements)

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“…The temperature dependence of the luminescence spectra of localized excitons qualitatively agrees with our proposed model, indicating that the model can be developed for a general case (i.e., 3D, 2D, 1D, 0D) for localized excitons such that it reproduces, quantitatively, all the anomalous temperature behaviors of localized-state luminescence. The main reason this model can be generalized is that the model of such localized electronic states is assumed to be a distribution function of energy and is expected to be an ensemble with a Gaussian-type density of states [32][33][34]. It is important to note that the main difference between 2D TMDCs and GaAs quantum wells is the much smaller size of the exciton Bohr radius (∼0.5 nm) in a TMDC ML, compared to ∼10 nm in GaAs quantum wells [35].…”

Section: Introductionmentioning

confidence: 99%

Alloying effect on bright–dark exciton states in ternary monolayer Mo_xW_1–xSe₂

et al. 2017

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Binary transition metal dichalcogenides (TMDCs) in the class MX 2 (M = Mo, W; X = S, Se) have been widely investigated for potential applications in optoelectronics and nanoelectronics. Recently, alloybased monolayers of TMDCs have provided a stable and versatile technique to tune the physical properties and optimize them for potential applications. Here, we present experimental evidence for the existence of an intermediate alloy state between the MoSe 2 -like and the WSe 2 -like behavior of the neutral exciton (X 0 ) using temperature-dependent photoluminescence (PL) of the monolayer Mo x W 1-x Se 2 alloy. The existence of a maximum PL intensity around 120 K can be explained by the competition between the thermally activated bright states and the non-radiative quenching of the bright states. Moreover, we also measured localized exciton (X B ) PL peak in the alloy and the observed behavior agrees well with a model previously proposed for the 3D case, which indicates the theory also applies to 2D systems. Our results not only shed light on bright-dark states and localized exciton physics of 2D semiconductors, but also offer a new route toward the control of the bright-dark transition and tailoring optical properties of 2D semiconductors through defect engineering.

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Section: Introductionmentioning

confidence: 99%

Alloying effect on bright–dark exciton states in ternary monolayer Mo_xW_1–xSe₂

et al. 2017

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“…Strong quantum confinement and reduced dielectric screening favours the formation of Coulomb-bound quasiparticle complexes [14][15][16] , including those bound to atomic crystal defects. Bound excitons in 2D TMDs can stem from different origins such as two-body type [17][18][19] where at least one of the two particles, electron and hole, is strongly localized to a defect, and three-or fourbody type 20,21 , which can be described as a free exciton bound to a neutral or charged defect 22,23 . Interestingly, in both cases, bound excitons can be partially composed of Bloch states such that the valley degree of freedom can be accessed 23,24 .…”

Section: Introductionmentioning

confidence: 99%

Dilute Acceptor-bound Excitons in a Monolayer Semiconductor

Loh

Xuan

Águila³

et al. 2023

Preprint

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Atomic defects in two-dimensional (2D) semiconductors are promising single exciton traps for achieving quantum emission. However, excessively high density of defects often makes it impractical to optically address the quantum nature of such quasi-particles, preventing strategic exciton engineering. Here, we report a versatile strategy for dilute acceptor impurity doping of monolayer WS2, which enables the study of isolated bound excitons. We observe two distinct types of acceptor-bound excitons: one of them is characterized by a large binding energy, allowing its observation at room temperature and the other by an extremely narrow linewidth (< 1 meV), showing strong resemblance to quantum emitters in WSe2. Polarization-resolved spectroscopy and magnetic field dependence reveal their strong contribution of free exciton character. In particular, the latter type exhibits characteristics of acceptor-bound dark excitons. Our work demonstrates dilute impurity doping as a promising strategy towards optically addressable quantum states in monolayer semiconductors.

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Optical Properties of Bound and Localized Excitons and of Defect States

Cited by 2 publications

References 46 publications

Alloying effect on bright–dark exciton states in ternary monolayer Mo_xW_1–xSe₂

Alloying effect on bright–dark exciton states in ternary monolayer Mo_xW_1–xSe₂

Dilute Acceptor-bound Excitons in a Monolayer Semiconductor

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Optical Properties of Bound and Localized Excitons and of Defect States

Cited by 2 publications

References 46 publications

Alloying effect on bright–dark exciton states in ternary monolayer MoxW1–xSe2

Alloying effect on bright–dark exciton states in ternary monolayer MoxW1–xSe2

Dilute Acceptor-bound Excitons in a Monolayer Semiconductor

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Alloying effect on bright–dark exciton states in ternary monolayer Mo_xW_1–xSe₂

Alloying effect on bright–dark exciton states in ternary monolayer Mo_xW_1–xSe₂