Picosecond Carrier Dynamics in Narrow-Gap Semiconductors studied by Terahertz Radiation Pulses

Adomavičius, R.; Šustavičiūtė, R.; Krotkus, A.

doi:10.1007/978-1-4020-8425-6_10

Cited by 7 publications

(4 citation statements)

References 1 publication

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“…Previous monochromatic investigations of wide-bandgap compositions of Hg 1−x Cd x Te in the near-IR spectral range succeeded in extracting average collective relaxation times on the order of 0.5 to 2 ps (25). A spectrally integrated pump-probe study of a narrow-bandgap composition (x = 0.2) in the terahertz spectral range arrived at a similar conclusion (26).…”

Section: Introductionmentioning

confidence: 71%

Ultrafast nonlocal collective dynamics of Kane plasmon-polaritons in a narrow-gap semiconductor

et al. 2019

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The observation of ultrarelativistic fermions in condensed-matter systems has uncovered a cornucopia of novel phenomenology as well as a potential for effective ultrafast light engineering of new states of matter. While the nonequilibrium properties of two- and three-dimensional (2D and 3D) hexagonal crystals have been studied extensively, our understanding of the photoinduced dynamics in 3D single-valley ultrarelativistic materials is, unexpectedly, lacking. Here, we use ultrafast scanning near-field optical spectroscopy to access and control nonequilibrium large-momentum plasmon-polaritons in thin films of a prototypical narrow-bandgap semiconductor Hg0.81Cd0.19Te. We demonstrate that these collective excitations exhibit distinctly nonclassical scaling with electron density characteristic of the ultrarelativistic Kane regime and experience ultrafast initial relaxation followed by a long-lived highly coherent state. Our observation and ultrafast control of Kane plasmon-polaritons in a semiconducting material using light sources in the standard telecommunications fiber-optics window open a new avenue toward high-bandwidth coherent information processing in next-generation plasmonic circuits.

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Section: Introductionmentioning

confidence: 71%

Ultrafast nonlocal collective dynamics of Kane plasmon-polaritons in a narrow-gap semiconductor

et al. 2019

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“…It must be noted that the free carrier influence on the THz generation strongly depends on their energy relaxation time. Thus in narrow band-gap semiconductors the THz generation is almost unaffected due to ∆t (ps) a relatively large electron mass during the first few picoseconds after the photoexcitation [20].…”

Section: Resultsmentioning

confidence: 99%

Study of surface electric field and photocarrier dynamics in InAs by means of a modified double-pump-pulse terahertz emission method

Beleckaitė¹,

Burakauskas²,

Adomavičius³

2018

physics

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In this study we report the investigation of terahertz (THz) emission efficiency dynamics in p-type InAs using a double-pump-pulse (DPP) THz emission method. We also suggest a novel modification of the standard DPP method which allows us to measure the indirectly modulated THz pulse. The obtained results reveal that the first optical pulse increases the free carrier concentration and enhances the surface electric field. This field prevents perpendicular but improves parallel to the surface electric dipole formation after sample excitation with the second optical pulse. Our suggested method is shown to be a more precise and sensitive way to study electric fields and photocarrier dynamics in semiconductors after photoexcitation.

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“…However, experiments have shown that average THz power radiated from the surfaces of InSb and Cd 1−x Hg x Te with x = 0, 0.2 and 0.3 is more than two orders of magnitude smaller than from the surface of InAs [143,148]. The reduced efficiency of THz emission from InSb was explained by photoexcited electron transfer to subsidiary conduction band L valleys with a large electron effective mass [143], whereas in the case of Cd 1−x Hg x Te the main reason for weak THz emission is, most probably, large non-parabolicity of the conduction band [149].…”

Section: Inas and Other Narrow-gap Semiconductorsmentioning

confidence: 98%

Semiconductors for terahertz photonics applications

Krotkus¹

2010

J. Phys. D: Appl. Phys.

108

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Abstract:Generation and measurement of ultrashort, sub-picosecond pulses of electromagnetic radiation with their characteristic Fourier spectra that reach far into terahertz (THz) frequency range has recently become a versatile tool of the far-infrared spectroscopy and imaging. This technique -THz time-domain spectroscopy, in addition to a femtosecond pulse laser, requires semiconductor components manufactured from materials with a short photoexcited carrier lifetime, high carrier mobility, and large dark resistivity. Here we will review most important developments in the field of investigation of such materials. Main characteristics of low-temperature-grown or ion-implanted GaAs and semiconducting compounds sensitive in the wavelength ranges around 1 µm and 1.5 µm will be surveyed. The second part of the paper is devoted to the effect of surface emission of THz transients from semiconductors illuminated by femtosecond laser pulses. Main physical mechanisms leading to this emission as well as their manifestation in various crystals will be described.

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Picosecond Carrier Dynamics in Narrow-Gap Semiconductors studied by Terahertz Radiation Pulses

Cited by 7 publications

References 1 publication

Ultrafast nonlocal collective dynamics of Kane plasmon-polaritons in a narrow-gap semiconductor

Ultrafast nonlocal collective dynamics of Kane plasmon-polaritons in a narrow-gap semiconductor

Study of surface electric field and photocarrier dynamics in InAs by means of a modified double-pump-pulse terahertz emission method

Semiconductors for terahertz photonics applications

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