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Proceedings Paper

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
Author(s): Subhananda Chakrabarti; Sourav Adhikary; Nilanjan Halder; Yigit Aytac; A. G. U. Perera
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Paper 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 (In0.21Al0.21Ga0.58As) 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.Hz1/2/W at a bias of 0.3V.

Paper Details

Date Published: 31 May 2012
PDF: 6 pages
Proc. SPIE 8353, Infrared Technology and Applications XXXVIII, 835338 (31 May 2012); doi: 10.1117/12.918988
Show Author Affiliations
Subhananda Chakrabarti, Indian Institute of Technology Bombay (India)
Sourav Adhikary, Indian Institute of Technology Bombay (India)
Nilanjan Halder, Indian Institute of Technology Bombay (India)
Yigit Aytac, Georgia State Univ. (United States)
A. G. U. Perera, Georgia State Univ. (United States)

Published in SPIE Proceedings Vol. 8353:
Infrared Technology and Applications XXXVIII
Bjørn F. Andresen; Gabor F. Fulop; Paul R. Norton, Editor(s)

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