Dynamics of hot carrier cooling in photo-excited GaAs

Leheny, R. F.; Shah, Jagdeep; Fork, R. L.; Shank, C. V.; Migus, A.

doi:10.1016/0038-1098(79)90393-4

Cited by 205 publications

(57 citation statements)

References 7 publications

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“…The average absorbed laser energy density is a function of excitation fluence and probe depth. This model is consistent with the expected fast electronic equilibration [24] and compara- tively slow rate of phonon emission [21] and ambipolar diffusion in a dense plasma [25]. In order to compare disordering time scales, the time required for the diffraction intensity to drop to 1=e of its original value ( 1=e ) is used.…”

Section: Institut Für Experimentelle Physik Universität Duisberg-esssupporting

confidence: 62%

Carrier-Density-Dependent Lattice Stability in InSb

et al. 2007

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The ultrafast decay of the x-ray diffraction intensity following laser excitation of an InSb crystal has been utilized to observe carrier dependent changes in the potential energy surface. For the first time, an abrupt carrier dependent onset for potential energy surface softening and the appearance of accelerated atomic disordering for a very high average carrier density have been observed. Inertial dynamics dominate the early stages of crystal disordering for a wide range of carrier densities between the onset of crystal softening and the appearance of accelerated atomic disordering. DOI: 10.1103/PhysRevLett.98.125501 PACS numbers: 63.20.Kr, 61.10.ÿi, 64.70.Dv, 78.47.+p First-order phase transitions and chemical reactions require crossing a transition state on the potential energy surface (PES). Characterizing the topography of the energy landscape in the vicinity of the transition state represents the key step to understanding the pathway followed during a chemical reaction or first-order phase transition. The experimental and theoretical characterization of these far from equilibrium regions of the PES has proven to be very difficult because of the vanishingly short time spent near the transition state and the multitude of degrees of freedom that influence chemical and physical transformations in the condensed phase. Time-resolved x-ray scattering experiments provide a window for observing the structural dynamics that occur during certain physical transformations. This is achieved by using femtosecond (fs) x-ray pulses to monitor laser initiated dynamics, selectively track the time-dependent evolution of nonequilibrium atomic structures, and extract the shape of a photoinduced PES [1][2][3][4].This approach has proven crucial to investigating the influence of carrier excitation on the stability of tetrahedrally bonded semiconductors. Theoretical, experimental, and simulation studies of these systems indicate that extreme carrier densities destabilize the crystal structure and lead to nonthermal melting [3,[5][6][7][8][9][10][11][12][13][14][15][16][17]. Theoretical studies predict a rapid reduction in the shear restoring force when the excited carrier density exceeds a few percent of the valence band electron density [5][6][7]. A further doubling of the carrier density eliminates the shear restoring force, transforms the room temperature potential energy minimum into a saddle point, and leads to accelerated atomic disordering.The initial ultrafast x-ray diffraction studies of laserexcited InSb at the Sub-Picosecond Pulse Source (SPPS) determined that inertial atomic displacements on a lasersoftened potential energy surface dominate the response to intense optical excitation during the first 500 fs for a range of laser fluences [3]. This predominance of inertial dynamics in a wide fluence range had not been predicted by either theory or simulation. While the studies of Lindenberg et al. [3] and Gaffney et al. [15] covered the mean carrier density range over which theory predicted crystal stability to r...

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Section: Institut Für Experimentelle Physik Universität Duisberg-esssupporting

confidence: 62%

Carrier-Density-Dependent Lattice Stability in InSb

et al. 2007

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“…15 It should be noted that Ram~n scattering measures LO phonon with a specific wave vector determined by the incident and scattered photon wave vectors. For the backscatterirg geometry and photon energy we use, the LO phonons have wave vectors Q=7.5xl0 5 LO phonons generated by the relaxation of hot electrons in GaAs has a maximum very close to this wave vector . 16 Thus Rama1, scattering is a fairly sensitive probe of the nonequilibrium LO phonons generated by the ·relaxation of hot electrons in bulk GaAs.…”

Section: Resultsmentioning

confidence: 99%

“…The di~advantages of these optical techniques are that they do not provide info~reation on the phonons which are excited by the cooling electrons. For example, Leheny et al 5 have found that the cooling rate of photoexcited hot electrons in bulk GaAs decreased when the electron density was increased to above 10 17 cm-3 . Leheny et al 5 suggested that this effect can be explained by the screening of the Frohlich electronlongitudinal opticai (LO) phonon interaction.…”

Section: Introductionmentioning

confidence: 99%

“…For example, Leheny et al 5 have found that the cooling rate of photoexcited hot electrons in bulk GaAs decreased when the electron density was increased to above 10 17 cm-3 . Leheny et al 5 suggested that this effect can be explained by the screening of the Frohlich electronlongitudinal opticai (LO) phonon interaction. Subsequent work has shown that the observed carrier uensity was too low for screening effects to be significant.…”

Section: Introductionmentioning

confidence: 99%

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Subpicosecond Raman Study of Hot Electrons and Hot Phonons in GaAs

Kim

1991

Light Scattering in Semiconductor Structures and Superlattices

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“…(l2 l3 ,l4) The importance of the screening of electron-phonon interaction has been established. (13) Carrier relaxation in two-dimensional quantum wells (l5) and velocity overshoot of electrons in a high electric field (l6) have been investigated. Super high-density (>1020 cm-3) plasma has been generated (l7) by using picosecond pulses and studied by observing the resulting short-pulse semiconductor laser dynamics.…”

Section: Investigation Of Hot Carrier Relaxation With Picosecond Lasementioning

confidence: 99%

Investigation of Hot Carrier Relaxation With Picosecond Laser Pulses

Shah¹

1981

J. Phys. Colloques

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Dynamics of hot carrier cooling in photo-excited GaAs

Cited by 205 publications

References 7 publications

Carrier-Density-Dependent Lattice Stability in InSb

Carrier-Density-Dependent Lattice Stability in InSb

Subpicosecond Raman Study of Hot Electrons and Hot Phonons in GaAs

Investigation of Hot Carrier Relaxation With Picosecond Laser Pulses

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