Sequential resonant tunneling through a multiquantum well superlattice

Abstract

We report the observation of two negative conductance regions in the low-temperature photocurrent-voltage characteristic of tight-binding multiquantum well (35 periods) 1-μm-thick Al0.48 In0.52As/ Ga0.47 In0.53As superlattices grown by molecular beam epitaxy. The two peaks occur at voltages corresponding to a potential energy drop across the superlattice period equal to the energy differences between the first two excited states and the ground state of the quantum wells. This provides direct evidence of sequential resonant tunneling between the ground and excited states of adjacent wells alternated with intrawell energy relaxation.