Thickness-tunable terahertz plasma oscillations in a semiconductor slab excited by femtosecond optical pulses

Journal Article · Tue Jul 15 00:00:00 EDT 2008 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PHYSREVB.78.035328· OSTI ID:21143600

Glinka, Y D; Maryenko, D; Smet, J H ^[1]

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1. Max-Planck-Institut fur Festkoerperforschung, Heisenberg Str. 1, 70569 Stuttgart (Germany)

We report on the observation of terahertz oscillations in an electron-hole plasma optically excited by a femtosecond pulse in the {mu}m-sized slab of low-temperature-grown-GaAs (LT-GaAs) grown on the GaAs substrate. The frequency of oscillations is shown to be inversely proportional to the slab thickness. It is suggested that the LT-GaAs slab serves as a resonant cavity for traveling plasma waves, which have been generated as a consequence of the shock interaction of photoexcited electron plasma with the GaAs/LT-GaAs interface. The instantaneous diffusion of photoexcited plasma inward the material is driven by the density gradient over the Beer's law distributed carrier population and is evidenced to be a main reason of the shock interaction in the localized plasma. The frequencies of oscillations observed are 3.5 times larger that the inverse electron transit time in the LT-GaAs slab, suggesting the 'ballistic' regime for plasma wave propagation to occur. The oscillations have been observed in the photocurrent autocorrelation measurements. The dynamical electric field at the GaAs/LT-GaAs interface arising due to the instantaneous diffusion of photoexcited electrons inward the material was studied through the transient reflectivity change responses, which have been measured simultaneously with photocurrent.

• OSTI ID: 21143600
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Vol. 78, Issue 3; Other Information: DOI: 10.1103/PhysRevB.78.035328; (c) 2008 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CARRIERS
CAVITY RESONATORS
DIFFUSION
ELECTRIC FIELDS
ELECTRONS
EXCITATION
GALLIUM ARSENIDES
INTERACTIONS
INTERFACES
OSCILLATIONS
PLASMA WAVES
PULSES
REFLECTIVITY
SEMICONDUCTOR MATERIALS
SLABS
SOLID-STATE PLASMA
SUBSTRATES
THICKNESS
THZ RANGE
VELOCITY