Investigation of the quantum dot infrared photodetectors dark current

Quantum dot infrared photodetectors (QDIPs) are more efficient than other types of semiconductor based photodetectors; so it has become an actively developed field of research. In this paper quantum dot infrared photodetector dark current is evaluated theoretically. This evaluation is based on the model that was developed by Ryzhii et al. Here it is assumed that both thermionic emission and field-assisted tunneling mechanisms determine the dark current of QDIPs; moreover we have considered Richardson effect, which has not been taken into account in previous research. Then a new formula for estimating average number of electrons in a quantum dot infrared photodetector is derived. Considering the Richardson effect and field-assisted tunneling mechanisms in the dark current improves the accuracy of algorithm and causes the theoretical data to fit better in the experiment. The QDiPs dark current temperature and biasing voltage dependency, contribution of thermionic emission and field-assisted tunneling at various temperatures and biasing voltage in the QDIPs dark current are investigated. Moreover, the other parameter effects like quantum dot (QD) density and QD size effect on the QDIPs dark current are investigated. (C) 2011 Elsevier Ltd. All rights reserved.