Heterostructure band engineering of type-II InAs/GaSb superlattice based longwave infrared photodiodes using unipolar current blocking barriers

N. Gautam; E. Plis; H. S. Kim; M. N. Kutty; S. Myers; A. Khoshakhlagh; L. R. Dawson; S. Krishna

doi:10.1117/12.849889

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3 May 2010 Heterostructure band engineering of type-II InAs/GaSb superlattice based longwave infrared photodiodes using unipolar current blocking barriers

N. Gautam, E. Plis, H. S. Kim, M. N. Kutty, S. Myers, A. Khoshakhlagh, L. R. Dawson, S. Krishna

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Proceedings Volume 7660, Infrared Technology and Applications XXXVI; 76601T (2010) https://doi.org/10.1117/12.849889
Event: SPIE Defense, Security, and Sensing, 2010, Orlando, Florida, United States

Abstract

We report heterojunction bandgap engineered long wave infrared (LWIR) photodetectors based on type-II InAs/GaSb strained layer superlattices (SLS) which show significant improvement in performance over conventional PIN devices. For this study, a device with unipolar barriers but same absorber region as PIN has been studied and compared. Unipolar barriers reduce the tunneling currents and SRH recombination current in the active region due to reduced electric field drop across the active region, while maintaining the photocurrent level. Moreover, they also reduce the diffusion current by blocking the minority carriers from the two sides of the junction. We report three orders of magnitude reduction in the dark current with the use of unipolar barriers. The reduction in the dark current results in significant improvement in signal to noise ratio, resulting in measured specific detectivity of 2×10¹⁰ (cm-√Hz)/W and dark current density of 8.7 mA/cm² at -0.5 V applied bias, for the 50% cutoff wavelength of 10.8μm.

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N. Gautam, E. Plis, H. S. Kim, M. N. Kutty, S. Myers, A. Khoshakhlagh, L. R. Dawson, and S. Krishna "Heterostructure band engineering of type-II InAs/GaSb superlattice based longwave infrared photodiodes using unipolar current blocking barriers", Proc. SPIE 7660, Infrared Technology and Applications XXXVI, 76601T (3 May 2010); https://doi.org/10.1117/12.849889

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