Topic
Screening effect
About: Screening effect is a research topic. Over the lifetime, 942 publications have been published within this topic receiving 15139 citations.
Papers published on a yearly basis
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Papers
TL;DR: It is demonstrated that the amplitude and polarity of the photocurrent in the gated vertical heterostructures can be readily modulated by the electric field of an external gate to achieve a maximum external quantum efficiency of 55% and internal quantum efficiency up to 85%.
Abstract: Layered materials of graphene and MoS2, for example, have recently emerged as an exciting material system for future electronics and optoelectronics. Vertical integration of layered materials can enable the design of novel electronic and photonic devices. Here, we report highly efficient photocurrent generation from vertical heterostructures of layered materials. We show that vertically stacked graphene–MoS2–graphene and graphene–MoS2–metal junctions can be created with a broad junction area for efficient photon harvesting. The weak electrostatic screening effect of graphene allows the integration of single or dual gates under and/or above the vertical heterostructure to tune the band slope and photocurrent generation. We demonstrate that the amplitude and polarity of the photocurrent in the gated vertical heterostructures can be readily modulated by the electric field of an external gate to achieve a maximum external quantum efficiency of 55% and internal quantum efficiency up to 85%. Our study establishes a method to control photocarrier generation, separation and transport processes using an external electric field. Efficient photocurrent generation, which can be tuned by the electric field of a gate to reach both high external and internal quantum efficiencies, is shown to occur in vertical heterostructures comprising graphene, MoS2 and metals.
1,237 citations
TL;DR: In this article, the static polarization function is calculated in two-dimensional graphite and used for the calculation of the conductivity limited by charged-impurity scattering, and the mobility remains independent of the Fermi energy.
Abstract: The static polarization function is calculated in two-dimensional graphite and used for the calculation of the conductivity limited by charged-impurity scattering. The conductivity increases in proportion to the electron concentration and the mobility remains independent of the Fermi energy, in qualitative agreement with experiments. The screening increases in proportion to temperature at sufficiently high temperatures in contrast to the behavior in conventional two-dimensional systems, leading to the mobility increase proportional to the square of temperature.
936 citations
TL;DR: It is found that a change in the number of 3d electrons in Fe is only screened to about 50% inside the Fe atom where the change was made, although perfect screening was expected for a metallic system like Fe.
Abstract: The effective Coulomb interaction between the localized electrons is calculated for Fe and Ce. It is found that a change in the number of 3d electrons in Fe is only screened to about 50% inside the Fe atom where the change was made, although perfect (100%) screening was expected for a metallic system like Fe. In Ce, on the other hand, the screening is very efficient. The difference is discussed. For Ce the calculated Coulomb interaction (6 eV) is in satisfactory agreement with experiment, while the result (6 eV) for Fe is surprising large.
929 citations
TL;DR: It is shown that the onset of collective behaviour such as Coulomb screening and plasmon scattering exhibits a distinct time delay of the order of the inverse plasma frequency, that is, several 10-14 seconds after ultrafast excitation of an electron–hole plasma in GaAs.
Abstract: Electrostatic coupling between particles is important in many microscopic phenomena found in nature. The interaction between two isolated point charges is described by the bare Coulomb potential, but in many-body systems this interaction is modified as a result of the collective response of the screening cloud surrounding each charge carrier. One such system involves ultrafast interactions between quasi-free electrons in semiconductors-which are central to high-speed and future quantum electronic devices. The femtosecond kinetics of nonequilibrium Coulomb systems has been calculated using static and dynamical screening models that assume the instantaneous formation of interparticle correlations. However, some quantum kinetic theories suggest that a regime of unscreened bare Coulomb collisions might exist on ultrashort timescales. Here we monitor directly the temporal evolution of the charge-charge interactions after ultrafast excitation of an electron-hole plasma in GaAs. We show that the onset of collective behaviour such as Coulomb screening and plasmon scattering exhibits a distinct time delay of the order of the inverse plasma frequency, that is, several 10(-14) seconds.
678 citations
TL;DR: These findings are helpful to better understand the tightly bound exciton properties in strongly quantum-confined systems and provide a simple approach to the selective and separate generation of excitons or trions with potential applications in excitonic interconnects and valleytronics.
Abstract: Photoluminescence (PL) properties of single-layer MoS2 are indicated to have strong correlations with the surrounding dielectric environment. Blue shifts of up to 40 meV of exciton or trion PL peaks were observed as a function of the dielectric constant of the environment. These results can be explained by the dielectric screening effect of the Coulomb potential; based on this, a scaling relationship was developed with the extracted electronic band gap and exciton and trion binding energies in good agreement with theoretical estimations. It was also observed that the trion/exciton intensity ratio can be tuned by at least 1 order of magnitude with different dielectric environments. Our findings are helpful to better understand the tightly bound exciton properties in strongly quantum-confined systems and provide a simple approach to the selective and separate generation of excitons or trions with potential applications in excitonic interconnects and valleytronics.
636 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2025 | 2 |
| 2024 | 2 |
| 2023 | 10 |
| 2022 | 26 |
| 2021 | 36 |
| 2020 | 29 |