Hot electron dynamics study by terahertz radiation from large aperture GaAs p-i-n diodes

Subpicosecond electromagnetic pulses having tetrahertz (THz) bandwidths have been generated from large aperture GaAs p-i-n diodes under bias by illumination with femtosecond optical pulses. The amplitude and shape of the radiated pulses change with the applied bias and the wavelength of the optical pulses illuminating the p-i-n diode. Comparing this radiation with THz radiation from large aperture Si p-i-n diodes provides evidence of velocity overshoot in the transient response of optically injected electrons in GaAs.