Characterization of self-assembled InGaAs/InGaP quantum dot mid-infrared photoconductive detectors grown by low-pressure MOCVD

7 April 1999

proceedings article
Published by SPIE-Intl Soc Optical Eng

p. 371-380
https://doi.org/10.1117/12.344572

Abstract

We report the first self-assembled InGaAs/InGaP quantum dot intersubband infrared photoconductive detectors (QDIPs) grown on semi-insulating GaAs substrate by low pressure metal organic chemical vapor deposition (MOCVD). The InGaAs quantum dots were constructed on an InGaP matrix as self assembling in Stranski-Krastanow growth mode in optimum growth conditions. The detector structure was prepared for single layer and multi-stacked quantum dots for active region. Normal incident photoconductive response was observed at a peak wavelength of 5.5 micrometer with a high responsivity of 130 mA/W, and a detectivity of 4.74 X 10⁷ cm Hz^1/2/W at 77 K for multi-stack QDIP. Low temperature photoresponse of the single quantum dot photodetector was characterized. Peak response was obtained between 16 K and 60 K. The detailed dark current noise measurements were carried on single and multistack quantum dot infrared detectors. High photoconductive gain as 7.6 X 10³ biased at 0.5 V results in increasing the intersubband carrier relaxation time as two order of magnitude compared quantum well infrared photodetectors.

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