Influence of doping density on the normal incident absorption of quantum-dot infrared photodetectors

摘要

The influences of doping densities at the quantum-dot (QD) region for 30-period InAs/GaAs quantum-dot infrared photodetectors (QDIPs) are investigated. The InAs/GaAs QDIPs with a lower doping density can operate at high responsivity and high background-limited-performance temperature. Also observed is the decreasing photocurrent ratio of s/p-polarized lights for the QDIPs with increasing QD doping density. Compared to the similar photocurrent ratio of s/p-polarized lights for the GaAs/AlGaAs quantum-well infrared photodetectors at different applied voltages, the observed voltage-dependent response ratio for QDIPs is attributed to the strong scattering characteristics of QDs occupied with photoexcited electrons for electron transport through the QD region.