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Schlagwörter:
Carrier density
Carrier relaxation times
Materials properties
Carbides
Carrier generation
Zusammenfassung:
The terahertz (THz) conductivity of photoinduced charge carriers in two common polytypes of silicon carbide, 3C-SiC and 6H-SiC, is studied on picosecond time scales using an optical-pump THz-probe technique. We find that the conductivity, measured from 0.7 to 3 THz, is well described by the Drude model, and obtain a velocity relaxation time of 75 fs, independent of sample and charge-carrier density. In contrast, the carrier relaxation rates in the two polytypes differ by orders of magnitude: in 6H- and 3C-SiC, recombination proceeds on a time scale of few picoseconds and beyond nanoseconds, respectively.
