HYPERABRUPT CURRENT SWITCHING IN GAAS/ALAS SUPERLATTICES

We have observed extremely large hyperabrupt changes spanning many orders of magnitude in superlattice current at temperatures ranging from 55-350K. Current is in the 10pA range before threshold and rises abruptly to over 10 mA at 55K, a change of nine orders of magnitude for a voltage change of about 1.0mV. This instantaneous current change is far larger than space charge limited current increases previously reported for bulk semiconductors. A native defect located in the superlattice barriers controls the magnitude of prethreshold current. This defect has a strong temperature and electric field dependent tunneling emission to the superlattice quantum well ground states. © 1991.