Demonstration of high responsivity(~2.16 A/W) and detectivity(~1011 Jones) in the long wavelength (~10.2&#956;m) from InGaAs/GaAs quantum dot infrared photodetector with quaternary InAlGaAs capping

Subhananda Chakrabarti; Sourav Adhikary; Nilanjan Halder; Yigit Aytac; A. G. U. Perera

doi:10.1117/12.918988

31 May 2012 Demonstration of high responsivity(~2.16 A/W) and detectivity(~10¹¹ Jones) in the long wavelength (~10.2μm) from InGaAs/GaAs quantum dot infrared photodetector with quaternary InAlGaAs capping

Subhananda Chakrabarti, Sourav Adhikary, Nilanjan Halder, Yigit Aytac, A. G. U. Perera

Author Affiliations +

Proceedings Volume 8353, Infrared Technology and Applications XXXVIII; 835338 (2012) https://doi.org/10.1117/12.918988
Event: SPIE Defense, Security, and Sensing, 2012, Baltimore, Maryland, United States

Abstract

The Self-assembled InGaAs/GaAs quantum dot infrared detectors (QDIPs) have emerged as a promising technology in many applications such as missile tracking, night vision, medical diagnosis, environmental monitoring etc. On account of the 3-D confinement of carriers in QDs, a number of advantages arise over the QW counterparts. Here we report a quaternary (InAlGaAs) capped In(Ga)As/GaAs QDIP. The samples were grown on a semi-insulating (001) GaAs substrate by solid source molecular beam epitaxy (MBE), and the dots were then capped with a combination of 30A quaternary (In_0.21Al_0.21Ga_0.58As) and 500Å of GaAs layer. Both the QD layer and the combination capping were repeated for 35 periods. The device was fabricated by conventional photolithography, ICP etching and metal evaporation technique. XTEM image of the sample depicted nice stacking of defect free quantum dot layers. The dark current is symmetric both for positive and negative bias with a low dark current density of 4.32x10^-6A/cm² at 77K and 1.6 x10 ^-3A/cm² at 200K at a bias of 2V. The high intense peak response observed at 10.2μm, with a very narrow spectral width (▵λ/λ) of 14% (▵λ is the FWHM), is probably due to bound-to-bound transition of carriers in the QDs. A very high responsivity of 2.16 A/W was measured at a bias of -0.40 Volt bias. The highest value of detectivity is measured to be ~10¹¹ cm.Hz^1/2/W at a bias of 0.3V.

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Subhananda Chakrabarti, Sourav Adhikary, Nilanjan Halder, Yigit Aytac, and A. G. U. Perera "Demonstration of high responsivity(~2.16 A/W) and detectivity(~10¹¹ Jones) in the long wavelength (~10.2μm) from InGaAs/GaAs quantum dot infrared photodetector with quaternary InAlGaAs capping", Proc. SPIE 8353, Infrared Technology and Applications XXXVIII, 835338 (31 May 2012); https://doi.org/10.1117/12.918988

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