Premium
Optical Nonlinearities and Carrier Transport in GaAs: EL2 at High Excitation Levels
Author(s) -
Jarasiunas K.,
Delaye Ph.,
Roosen G.
Publication year - 1993
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221750216
Subject(s) - picosecond , ambipolar diffusion , materials science , excitation , grating , optics , excited state , optoelectronics , polarization (electrochemistry) , electron mobility , electron , laser , chemistry , atomic physics , physics , quantum mechanics
Laser induced picosecond transient gratings are used to study carrier transport via free carrier and photorefractive nonlinearities in semi‐insulating undoped GaAs bulk crystals. Carrier lifetime (τ R = 1.5 ns), hole and ambipolar mobilities (μ h = 410 cm 2 V −1 s −1 , μ a = 760 cm 2 V −1 s −1 ) are measured directly and an electron mobility equal to 5200 cm 2 V −1 s −1 is calculated. The optical properties of highly excited GaAs reveal deep donor EL2 transformation and intracenter absorption under picosecond excitation. Rotation of the diffracted beam polarization is observed for the first time in orientation of the grating vector along the crystallographic axis [001]. This signal is attributed to a strain field at dislocations in LEC‐grown GaAs wafers.