Investigation of InAs/GaAs quantum-dot infrared photodetector with In 0.5 Ga 0.5 P dark current blocking layer

A novel InAs/GaAs quantum-dot infrared photodetector with an In0.5Ga0.5P dark current blocking layer for long-wavelength infrared (LWIR) detection has been developed in this work. Very low dark current densities were obtained at Vb=−0.5 V (10−10 A/cm−2) and Vb=+0.5 V (10−11 A/cm−2) at 77K. The normal incident responsivity up to 90 K was observed in this device. The background limited performance (BLIP) detectivity (D*BLIP) was found to be 3.36×109 cm-Hz1/2/W at λp=12.2 µm with a corresponding responsivity of 55 mA/W at Vb=−1.7 V and T=77K.