Abstract
The influences of doping densities at the quantum-dot (QD) region for 30-period InAsGaAs quantum-dot infrared photodetectors (QDIPs) are investigated. The InAsGaAs 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 sp -polarized lights for the QDIPs with increasing QD doping density. Compared to the similar photocurrent ratio of sp -polarized lights for the GaAsAlGaAs 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. © 2006 American Institute of Physics.