Ultrafast carrier diffusion in gallium arsenide probed with picosecond acoustic pulses
Abstract
We describe an experimental investigation of the generation and detection of picosecond acoustic-phonon pulses in a thin slab of GaAs using ultrashort optical pulses. Comparison of the optical phase variation with a simple theory for ambipolar diffusion indicates that carrier diffusion has a significant effect on the shape of the phonon pulses generated. The phonon pulse duration is measured to be ~25 ps, four times longer than that expected from optical-absorption considerations alone, indicating that hot carriers penetrate more than 100 nm into the sample during the phonon pulse generation process.
- Publication:
-
Physical Review B
- Pub Date:
- August 2001
- DOI:
- Bibcode:
- 2001PhRvB..64h1202W
- Keywords:
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- 73.50.-h;
- 43.35.+d;
- 62.65.+k;
- Electronic transport phenomena in thin films;
- Ultrasonics quantum acoustics and physical effects of sound;
- Acoustical properties of solids