EFFECT OF SELF ASSEMBLED QUANTUM DOTS ON CARRIER MOBILITY, WITH APPLICATION TO MODELING THE DARK CURRENT IN QUANTUM DOT INFRARED PHOTODETECTORS

Abstract

A theoretical method for calculating the electron mobility in quantum dot infrared photodetectors is developed. The mobility calculation is based on a time-dependent, finite-difference solution of the Boltzmann transport equation in a bulk semiconductor material with randomly positioned conical quantum dots. The quantum dots act as scatterers of current carriers, resulting in limiting their mobility. The calculated values of the mobility are used in a recently developed generalized drift-diffusion model for the dark current of the device in order to fix the overall current scale. The results of the model are verified by comparing the predicted dark current characteristics to those experimentally measured and reported for actual InAs/GaAs quantum dot infrared photodetectors. Finally, the effect of the several relevant device parameters, including the operating temperature and the quantum dot average density, is studied.