Free carrier and lattice-heating-induced changes to the reflectivity of epitaxial GeSi alloys following picosecond pulse excitation
Date
1992Source
Solid State CommunicationsVolume
82Issue
5Pages
325-328Google Scholar check
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Transient reflectivity characteristics for epitaxial Ge1-xSix (x=0, 0.05, 0.1, 0.25) alloys have been measured at λ = 0.575μm, using 2ps pump and probe pulses with photogenerated carrier densities up to 1019 cm-3. For all x we are able to separately determine negative (free carrier) and positive (lattice heating) contributions to the reflectivity change the relative contributions of the latter are found to increase with increasing x. The evolution of the free carrier part is dominated by carrier-temperature-dependent diffusion. © 1992.