Improved photoresponse of InAs/GaAs quantum dot infrared photodetectors by using GaAs1-xSbx strain reducing layer

The effect of a GaAs1-xSbx strain reducing layer on the performance of InAs/GaAs quantum-dot infrared photodetectors was investigated. The results suggest that increasing Sb composition x from 0 to 0.2 leads to an enhanced peak response and a pronounced narrowing of the band width of the spectral response from 3.3 to 1.5 mu m. For a photodetector with GaAs0.8Sb0.2 strain reducing layer, the best responsivity obtained is 533 mA/W, which is 380 times higher than that without strain reducing layer. In addition, the operating temperature increases from 50 to 90 K when increasing Sb composition from 0 to 0.2. (C) 2012 American Institute of Physics. [doi: 10.1063/1.3679132]