Sensitive Ultrafast THz Mobility Measurement.

We have developed a sensitive ultrafast technique for measuring the mobility of photocarriers in semiconductors from THz emission measurements in a magnetic field. In GaAs, this zero-background technique requires ∼10pJ/pulse photoexcitation, and can be easily implemented with an unamplified Ti:S laser. We have also investigated cyclotron emission from semi-insulating GaAs and InP at low temperatures (T<100K), and measured electron, light-hole and heavy-hole cyclotron emission as a function of pump photon energy. We see a resonant enhancement of the light-hole effective mass when the light-hole kinetic energy equals the optical phonon energy, similar to the well-known electron magneto-polaron resonance. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]