Laser hyperacoustic spectroscopy of single crystal germanium

Autor: Vitalyi Gusev, D. Yu. Parashchuk, N. V. Chigarev, Yu. S. Pan
Rok vydání: 2002
Předmět:
Zdroj: Journal of Experimental and Theoretical Physics. 94:627-636
ISSN: 1090-6509
1063-7761
Popis: Using a photothermal laser deflection technique the profiles of laser-induced hyperacoustic pulses in single crystal germanium were studied at a subnanosecond time resolution. It is shown that the hyperacoustic pulses are excited due to an electron-deformation interaction of photogenerated carriers with the crystal lattice, which is much more effective than the thermoelastic mechanism of the acoustic wave generation. Evolution of the hyperacoustic pulse profiles related to the diffraction and acoustic absorption effects was studied. An analysis of the hyperacoustic signal profiles allowed us to estimate the coefficient of ambipolar diffusion of the photogenerated charge carriers and the coefficient of hyperacoustic wave damping. It is established that the front of the electron-hole plasma laser-excited in germanium at room temperature propagates at a supersonic velocity.
Databáze: OpenAIRE