Influence of dislocation on high-electric-field property in semi-insulating GaAs

High-electric-field properties such as sub-linear I-V characteristic and low-frequency oscillations (LFOs) have been measured in a low-dislocation-density semi-insulating GaAs crystal. It is found that the sub-linear I-V behaviours and LFO waveforms measured at the cathodes where no dislocations exist are very stable but those measured at the cathodes where several dislocations are observed are not stable but more complicated, which is confirmed from Fourier-transform spectra of LFOs. It is explained that the high-electric-field properties observed here depend on the electrical inhomogeneities induced by the dislocations.