Performance analysis of polarization sensitive mid-infrared photodetector using anisotropic quantum dot

Abstract

In this study, normal incidence polarization sensitive photodetector has been proposed based on intraband transition of holes in valence band using InGaAs/GaAs quantum dots. The in-plane elongated dots have been considered for the analysis to get the polarization sensitive absorption for normal incidence of light. The dimensions of the dots and transitions are chosen such that the peak detection wavelength comes in mid-infrared spectral region. We have calculated the detector parameters such as absorption coefficient, quantum efficiency, photoconductive gain, photocurrent and dark current. The calculated absorption coefficient and photoconductive gain are found of the order of 10 4 m -1 and 10 5 , respectively. The impact of number of quantum dot layers on these parameters has been analyzed. We have found that increasing the number of quantum dot layers enhances the quantum efficiency and decreases the dark current of the device, but simultaneously photoconductive gain reduces drastically and because of this photocurrent of the devices also reduces. In spite of very low quantum efficiency of the photodetector with single QDs layer, it can produce a significantly high detectable photocurrent due to large photoconductive gain of the device.