Abstract
High frequency phonons are produced by the thermalization of photoexcited electronhole pairs in a semiconductor. Inelastic and elastic scattering processes determine the frequency down-conversion and diffusion of this thermal energy. Simple estimates of the anharmonic and isotope scattering processes suggest that the acoustic phonons will undergo a quasi-diffusive propagation process. In particular, non-equilibrium phonons high-resolution phonon-imaging experiments presented here show well defined ballistic pulses and sharp phonon-focusing caustics. We explain this discrepancy in terms of a phonon hot spot which acts to efficiently down-convert the high-frequency phonons very near the excitation spot. We present the first measurements of the size of a phonon hot spot, which depends upon excitation power.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Hensel, J.C., Dynes, R.C.: Phys. Rev. Lett.39, 969 (1977)
Kazakovtsev, D.V., Levinson, Y.B.: Sov. Phys. JETP61, 1318 (1985)
Kazakovtsev, D.V., Levinson, Y.B.: Phys. Status Solidi136, 425 (1986)
Guseinov, N.M., Orudzhev, G.S.: Sov. Phys. Solid State29, 1308 (1987)
Greenstein, M., Tamor, M.A., Wolfe, J.P.: Phys. Rev. B26, 5604 (1982)
Greenstein, M., Tamor, M.A., Wolfe, J.P.: Phys. Rev. B27, 7353 (1983)
Cabrera, B., Krauss, L.M., Wilczek, F.: Phys. Rev. Lett.55, 25, (1985)
Maris, H.J.: Phonon scattering in condensed matter V. Anderson, A.C., Wolfe, J.P. (eds.). Berlin, Heidelberg, New York: Springer 1986
Northrop, G.A., Wolfe, J.P.: Nonequilibrium phonon dynamics. Bron, W.E. (ed.). New York: Plenum Press 1985
Maris, H.J.: Nonequilibrium phonons in nonmetallic crystals. Eisenmenger, W., Kaplyanskii, A.A. (eds.) Chap. 1 Amsterdam: North-Holland 1986
This crystal was pulled from the melt using a MCZ (magnetic Czochralski) process to suppress defects. There are less than 5 ppm O2 and C impurities andp=2000 Ω-cm at 300 K.
Weis, O.: Z. Angew. Phys.26, 325 (1969)
These techniques are reviewed in Ref. 9. The elastic contants used here are those measured at 300K,C 11=1.658,C 12=0.639,C 44=0.796×1012 dynes/cm2, by McSkimin, H.J., Andreatch, Jr., P.: J. Appl. Phys.35, 2161 (1964)
Tamura, S.: Phys. Rev. B31, 2574 (1985)
Bron, W.E., Levinson, Y.B., O'Connor, J.M.: Phys. Rev. Lett.49, 209 (1982)
kazakovtsev, D.V., Levinson, Y.B.: Phys. Status Solidi96, 117 (1979)
Levinson, Y.B.: Nonequilibrium phonons in nonmetallic crystals. Eisenmenger, W., Kaplyanskii, A.A. (eds.), p. 91 Amsterdam: North-Holland 1986
Maris, H.J.: Phys. Rev. B28, 7033 (1983)
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Shields, J.A., Wolfe, J.P. Measurement of a phonon hot spot in photoexcited Si. Z. Physik B - Condensed Matter 75, 11–15 (1989). https://doi.org/10.1007/BF01313562
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF01313562