Performance improvement of long-wave infrared InAs/GaSb strained-layer superlattice detectors through sulfur-based passivation

► Sulfur is effective passivant for InAs/GaSb strained-layer superlattice detectors. ► Variable area diode array method was employed to test the passivation efficacy. ► Electrochemically deposited sulfur significantly improves detector performance. We report on effective sulfur-based passivation treatments of type-II InAs/GaSb strained layer superlattice detectors (100% cut-off wavelength is 9.8μm at 77K). The electrical behavior of detectors passivated by electrochemical sulfur deposition (ECP) and thioacetamide (TAM) was evaluated for devices of various sizes. ECP passivated detectors with a perimeter-to-area ratio of 1600cm−1 exhibited superior performance with surface resistivity in excess of 104Ωcm, dark current density of 2.7×10−3A/cm2, and specific detectivity improved by a factor of 5 compared to unpassivated devices (VBias=−0.1V, 77K).