Improved performance of high indium InGaAs photodetectors with InAlAs barrier

We report on the demonstration of an InP based In0.83Ga0.17As photodetector with an In-0.83 Al0.17As barrier, which is lattice-matched to the absorption layer. According to the comprehensive comparison with the photodetector without the barrier, the dark current is markedly reduced by inserting the InAlAs barrier. Although the photoresponse slightly decreases for the device with the InAlAs barrier, the detectivity remains higher than that of the reference device at room temperature and significantly increases at lower temperatures. These results indicate that InAlAs is a promising barrier layer in high-indium InGaAs photodetectors. (C) 2018 The Japan Society of Applied Physics