Device characteristics of self-assembled InAs/GaAs quantum dot infrared photodetectors

Abstract

We report some distinctive experimental results on device characteristics for three different kinds of n-i-n quantum dot infrared photodetector (QDIP) structures with an active layer of InAs QDs fabricated by using a self-assembling technique. The structure doped in the upper GaAs barrier clearly shows an infrared detection behavior up to 190 K over a broad range of lambda congruent to 3-10 mum, peaking at lambda(o) congruent to 5 mum, and the peak values of the apparent photocurrent and responsivity are similar to10(-8) A and 650 mA/W at 18 K, respectively. Based on comparative results from the photoresponse spectra and the corresponding responsivities, we have concluded that the QDIP structure doped in the upper GaAs barrier has the best device characteristics in the three structures investigated in this study.