Unipolar avalanche multiplication phenomenon in multiquantum well structures

Abstract

Unipolar electron impact ionization and multiplication in photodiodes consisting of GaAs/AlGaAs multiquantum well heterostructures have been observed. In these diodes, electrons generated by photon absorption and accelerated in the barrier regions scatter bound electrons from the donor-doped GaAs wells. Gain-per-well of 1.13±0.05 and total gain of 100 for the multiplication region have been demonstrated. The photodiodes exhibit high dark current which arises from thermionic emission and tunneling of electrons out of the wells.