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Proceedings Paper

Addressing surface leakage in type-II InAs/GaSb superlattice materials using novel approaches to surface passivation
Author(s): Eric A. DeCuir Jr.; John W. Little; Neil Baril
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Paper Abstract

Diminished performance due to poor chemical and electrical surface stability of InAs/GaSb SL photodetectors continues to be a major hurdle to the realization of the theoretically predicted high performance of this material system. Improved epitaxial growth conditions have yielded improvements in material quality over the past several years. However, surface instability resulting in electrical shunt pathways across the junction, and diminished device performance over time is still a major limiting factor for application of InAs/GaSb SL in long-wavelength infrared detectors. This study focuses on a two-step approach towards the successful surface passivation of long-wavelength InAs/GaSb superlattice structures. Two distinct sulfide chemical surface treatments were applied to inhibit the formation of native surface oxides and satisfy dangling bonds. This was followed by the application of a robust SU8-2 dielectric treatment on the mesa sidewalls to inhibit sulfide layer degradation and oxidation of the surface over time. A variable area diode analysis (VADA) technique employing diodes of variable diameter (40-400um) enabled the investigation of surface resistivity as a result of different passivation treatments. Temperature dependent studies of the dark current were used to understand the dominating current mechanisms.

Paper Details

Date Published: 16 September 2011
PDF: 8 pages
Proc. SPIE 8155, Infrared Sensors, Devices, and Applications; and Single Photon Imaging II, 815508 (16 September 2011); doi: 10.1117/12.895448
Show Author Affiliations
Eric A. DeCuir Jr., U.S. Army Research Lab. (United States)
John W. Little, U.S. Army Research Lab. (United States)
Neil Baril, U.S. Army RDECOM, CERDEC (United States)

Published in SPIE Proceedings Vol. 8155:
Infrared Sensors, Devices, and Applications; and Single Photon Imaging II
Manijeh Razeghi; Paul D. LeVan; Ashok K. Sood; Priyalal S. Wijewarnasuriya, Editor(s)

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