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Proceedings Paper

Impact of threading dislocation density on metamorphic InxGa1-xAs and InzGa1-zP p-i-n photodetectors on GaAs
Author(s): K. Swaminathan; T. J. Grassman; L.-M. Yang; D. Chmielewski; M. Mills; S. A. Ringel
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Paper Abstract

Bandgap tunability achievable using metamorphic epitaxy enables maximization of photodetector performance at target wavelengths. However, an increase in threading dislocation density (TDD), which is inherent for the growth of relaxed, lattice-mismatched layers, could offset this advantage and severely limit detector performance. In this regard, we are investigating the performance of InxGa1-xAs and InzGa1-zP p-i-n photodetectors as a function of TDD, by utilizing a number of different InxGa1-xAs buffer designs. In particular, internally lattice-matched metamorphic In0.20Ga0.80As and In0.68Ga0.32P individual p-i-n detectors are studied to optimize the buffer design and performance of optically-aligned In0.68Ga0.32P/In0.20Ga0.80As visible/near-infrared dual-photodetectors. Reverse-bias dark current density of In0.68Ga0.32P detectors were found to be extremely sensitive to TDD compared to that observed for In0.20Ga0.80As detectors. Nearidentical spectral response curves were obtained for both detectors as a function of TDD due to the relative insensitivity of the p-i-n detector structure to the minority carrier lifetime. A comprehensive comparison between the different graded buffer designs, TDD achieved and photodetector characteristics are presented.

Paper Details

Date Published: 19 March 2012
PDF: 8 pages
Proc. SPIE 8257, Optical Components and Materials IX, 82571A (19 March 2012); doi: 10.1117/12.908581
Show Author Affiliations
K. Swaminathan, The Ohio State Univ. (United States)
T. J. Grassman, The Ohio State Univ. (United States)
L.-M. Yang, The Ohio State Univ. (United States)
D. Chmielewski, The Ohio State Univ. (United States)
M. Mills, The Ohio State Univ. (United States)
S. A. Ringel, The Ohio State Univ. (United States)

Published in SPIE Proceedings Vol. 8257:
Optical Components and Materials IX
Shibin Jiang; Michel J. F. Digonnet; J. Christopher Dries, Editor(s)

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