PERPENDICULAR TRANSPORT-PROPERTIES OF A P-GAAS DELTA-DOPED SUPERLATTICE/N+-GAAS STRUCTURE/

The perpendicular transport properties of a p-GaAs/delta-doped superla ttice/n+-GaAs structure were studied at 300 and 77 K. An interesting S -shaped negative differential resistance (NDR), resulting mainly from avalanche multiplications within the superlattice region, was observed at 300 K. A different multistate NDR phenomenon and an interesting hy steresis behaviour were found at 77 K. The multistate NDR is attribute d to a sequential subavalanche multiplication process occurring within superlattice periods; holes created by avalanche multiplications play an important role in the transport properties. The hysteresis behavio ur at 77 K seems to be caused by the heavily accumulated holes, which cannot react synchronously with the applied electric field.