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The authors report on recent advances in the development of mid-, long-, and very long-wavelength infrared (MWIR, LWIR, and VLWIR) type-II InAs/GaSb superlattice infrared photodiodes. The residual carrier background of binary type-II InAs/GaSb superlattice photodiodes of cut-off wavelengths around 5 µm has been studied in the temperature range between 10 and 200 K. A four-point, capacitance-voltage technique on mid-wavelength and long-wavelength type-II InAs/GaSb superlattice infrared photodiodes reveal residual background concentrations around 5 × 10¹⁴ cm^-3. Additionally, recent progress towards LWIR photodiodes for focal plane array imaging applications is presented. Single element detectors with a cut-off wavelength, _c,50%, of 10.2 µm demonstrated detectivities of approximately 1 × 10¹¹ cmHz^1/2W^-1 and quantum efficiencies of 32% at the peak responsivity wavelength of around 7.9 µm. Furthermore, high-performance VLWIR single element photodiodes are discussed. The silicon dioxide passivation of VLWIR photodiodes is also presented, which resulted in an approximately 5 times increase of the sidewall resistivity. The latest developments in this material system lend further support for its use as a high-performance alternative for infrared optical systems compared to the current state-of-the-art imaging systems, especially those approaching the long-wavelength and very-long-wavelength infrared.

©2006 COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.