Modeling noise in superlattice quantum-well infrared photodetectors

Abstract

We propose a model that realistically describes the experimental noise curves of GaAs/AlGaAs quantum-well intersubband photodetectors and that, additionally, allows the determination of some important transport parameters of these devices. The analysis was based on the quantum mechanical calculation of the capture lifetime in a quantum well and on the assumption that the capture probability can be explicitly expressed as a function of the electronic thermal velocity at zero bias and of the saturation velocity at large bias. Our experimental and theoretical results point out that the plateau observed in the noise measurements at low temperature and low electric field is due to an extra conduction path through the miniband of the superlattice formed by the ground states of all the wells.