Perpendicular transport properties of a p-GaAs/δ-doped superlattice/n₊-GaAs structure

The perpendicular transport properties of a p-GaAs/δ-doped doped superlattice/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 NDR phenomenon and an interesting hysteresis behavior were found at 77 K. The multistate NDR is attributed 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 behavior at 77 K seems to be caused by the heavily accumulated holes, which cannot react synchronously with the applied electric field.