Study of hot phonons and hot carriers in GaAs under picosecond optical pulse excitation

Technical Report · Sun Apr 01 04:00:00 EST 1984

OSTI ID:6824866

Collins, C L

The ability of light scattering techniques to determine simultaneously many of the important properties of photoexcited electron-hole plasmas in GaAs was demonstrated. Scattering due to plasmons or coupled LO-plasmon modes can be used to determine the plasma density provided the spatial profile of the density is known. The distribution function and the drift velocity of the plasma in the direction of the laser beam can be determined from the SPE spectra. The fact that the plasma density can be determined independently of the distribution function enabled me to show that the electron distribution function in high density EHP in GaAs is nonthermal equilibrium within approx. 20 psec of excitation. This conclusion is consistent with previous experiments on photoexcited EHP in GaAs using picosecond lasers, although the form of the nonequilibrium distribution was not determined in the earlier measurements. At the moment there is very little information on the properties of transient high density EHP in semiconductors so it is too early to derive theoretical justifications for the power law distribution functions I deduced. However, one may speculate that this may have something to do with the slowing of hot carrier relaxation by emission of LO phonons due to screening of the Froehlich interaction. Also the rapid expansion of the EHP may have important consequence on the thermalization of the EHP.

• Research Organization: Lawrence Berkeley Lab., CA (USA)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 6824866
• Report Number(s): LBL-17825; ON: DE84013243
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
656001 -- Condensed Matter Physics-- Solid-State Plasma
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ARSENIC COMPOUNDS
ARSENIDES
BAND THEORY
BOLTZMANN EQUATION
CHARGE CARRIERS
COLLECTIVE EXCITATIONS
DATA
DIFFERENTIAL EQUATIONS
DISTRIBUTION FUNCTIONS
ELECTRON-HOLE DROPLETS
ELECTRON-PHONON COUPLING
ENERGY-LEVEL TRANSITIONS
EQUATIONS
EXCITATION
EXPERIMENTAL DATA
FUNCTIONS
GALLIUM ARSENIDES
GALLIUM COMPOUNDS
INFORMATION
LASERS
LIGHT SCATTERING
NUMERICAL DATA
PARTIAL DIFFERENTIAL EQUATIONS
PHONONS
PLASMA
PLASMONS
PNICTIDES
QUASI PARTICLES
SCATTERING
SOLID-STATE PLASMA