Diffusion of Photoexcited Holes in a Viscous Electron Fluid

Pusep, Yuri A.; Teodoro, M. D.; Laurindo, V.; Oliveira, E. R. Cardozo de; Gusev, G. M.; Бакаров, А. К.

doi:10.1103/physrevlett.128.136801

Cited by 12 publications

(7 citation statements)

References 19 publications

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“…To date, almost all commercialized photodetector devices are based on positive photoconductivity. The opposite NPC phenomenon has been widely demonstrated in inorganic semiconductors. − Various types of mechanisms/hypotheses have been proposed behind the NPC generation in these semiconductors. In the following few subsections, we will discuss the NPC phenomenon in inorganic semiconductors and the possible mechanism behind this feature.…”

mentioning

confidence: 99%

Negative Photoconductivity: Bizarre Physics in Semiconductors

Tailor

Aranda

Saliba

et al. 2022

ACS Materials Lett.

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Many gadgets in our daily life work on the photodetection principle. These photodetectors (such as silicon (Si), gallium arsenide (GaAs), and indium gallium arsenide (InGaAs)) work on the principle of positive photoconductivity (PPC), where conductivity increases with light illumination. However, an opposite phenomenon, where the conductivity decreases with light exposure, also known as negative photoconductivity (NPC), has been reported in various inorganic (doped-Si, PbTe, 2D materials), organic (graphene, carbon nanotubes), and organic–inorganic hybrid (halide perovskites) materials. The origin of NPC phenomena in a semiconductor is still debated though its application potential has recently reached far beyond photodetection. Here, we have critically analyzed the fundamental photophysics of NPC phenomena in semiconductors, discussed its mechanistic origin in detail, and demonstrated how it depends on various external factors, such as temperature, illumination intensity, humidity, doping concentration, etc. We also highlight the recent progress of NPC in ultrasensitive detection applications. Finally, we discussed the existing challenges and provided a roadmap about how NPC can be helpful in next-generation semiconductor optoelectronics.

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mentioning

confidence: 99%

Negative Photoconductivity: Bizarre Physics in Semiconductors

Tailor

Aranda

Saliba

et al. 2022

ACS Materials Lett.

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“…The PC measured in the mesoscopic channel as a function of the distance between the laser spot and PC probes 1 and 2 (diffusion profile) at various excitation energies is shown in figure 3(a). Technical details of the PC measurements can be found in [19] . Excitation of electron-hole pairs at an energy of 2.33 eV above the barrier gap reveals a minimum of the PC, while it is not detected at an excitation energy of 1.7 eV below the barrier gap, that is in the QW.…”

Section: Resultsmentioning

confidence: 99%

“…Furthermore, the hydrodynamic properties of dense electron-hole plasma were predicted in semiconductors in which the electron-electron, electron-hole and hole-hole collisions dominate over the collisions of electrons and holes with disorder [18]. Diffusion of photogenerated holes was recently studied in [19] by measuring photocurrent (PC) in viscous electron gas formed in high-mobility mesoscopic GaAs channel where hydrodynamics governs the transport properties of a bipolar electron-hole plasma. The PC was measured under specific conditions when, after photogeneration in AlGaAs barriers, holes tunneled into the GaAs QW, where they recombined with background electrons, which caused a decrease in the electron concentration and, consequently, in the PC.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of recombination in viscous electron–hole plasma in a mesoscopic GaAs channel

Pusep

Teodoro

Pusep

et al. 2023

J. Phys. D: Appl. Phys.

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The recombination dynamics is studied in viscous electron-hole plasma, consisting of electrons and photo-generated heavy and light holes, formed in high-mobility mesoscopic GaAs channel. It is shown that an increase in the pump power reduces the concentration and mobility of background electrons, which, in turn, slows down their recombination with photogenerated holes. At a critical pump power, the recombination time begins to decrease, which is a consequence of the transition of a viscous electron-hole plasma from the hydrodynamic regime to the Drude di¤usive regime. The observed transition occurs when the scattering of electrons with disorder begins to dominate over electron-electron scattering, which leads to the transformation of an inhomogeneous Poiseuille charge ow into a homogeneous di¤usion ow. As a result, an optical analogue of the Gurzhi effect has been found.

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“…For completeness, we first summarize some key aspects of the topological optical N-invariant in graphene's viscous Hall fluid. Interacting many-body electron systems in various 2D materials can be described by the hydrodynamic electron flow model when the momentum-conserving electron-electron scattering is dominant [21,23,[57][58][59][60][61][62][63]. The optical N-invariant classifies the electromagnetic topology in the presence of electron-electron interactions through the bulk atomistic susceptibility tensor.…”

Section: Optical N-invariantmentioning

confidence: 99%

Optical N-plasmon: topological hydrodynamic excitations in graphene from repulsive Hall viscosity

Sun,

Van Mechelen,

Bharadwaj

et al. 2023

New J. Phys.

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Edge states occurring in Chern and quantum spin-Hall phases are signatures of the topological electronic band structure in two-dimensional (2D) materials. Recently, a new topological electromagnetic phase of graphene characterized by the optical N-invariant was proposed. Optical N-invariant arises from repulsive Hall viscosity in hydrodynamic many-body electron systems, distinct from the Chern and Z2 invariants. In this paper, we introduce the topologically protected edge excitation -- optical N-plasmon of interacting many-body electron systems in the topological optical N-phase. These optical N-plasmons are signatures of the topological plasmonic band structure in 2D materials. We demonstrate that optical N-plasmons exhibit unique dispersion relations, stability against various boundary conditions and edge profiles when compared with the topologically trivial edge magneto plasmons. Based on the optical N-plasmon, we design an ultra sub-wavelength broadband topological hydrodynamic circulator, which is a chiral quantum radio-frequency circuit component crucial for information routing and interfacing quantum-classical computing systems. Furthermore, we reveal that optical N-plasmons can be effectively tuned by the neighboring dielectric environment without breaking the topological properties. Our work provides a smoking gun signature of topological electromagnetic phases occuring in two-dimensional materials arising from repulsive Hall viscosity.

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Diffusion of Photoexcited Holes in a Viscous Electron Fluid

Cited by 12 publications

References 19 publications

Negative Photoconductivity: Bizarre Physics in Semiconductors

Negative Photoconductivity: Bizarre Physics in Semiconductors

Dynamics of recombination in viscous electron–hole plasma in a mesoscopic GaAs channel

Optical N-plasmon: topological hydrodynamic excitations in graphene from repulsive Hall viscosity

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