Observations of high-field domains in GaxIn1 ? xSb Gunn diodes

The properties of high-field domains in GaxIn1-xSb Gunn diodes (0.4 < x < 0.82) have been studied by measuring the surface potential on the diodes. The domain velocities vary with the Ga composition x, 5.3?6.1×106 cm/s for0.8 > x > 0.55 and 10×106 cm/s for x = 0.4, but they are almost independent of the applied voltage, even if the electron concentration is increased by the impact ionisation in the domain at high applied voltages for the small-x samples.