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

We report on effective sulfur-based passivation treatments of type-II InAs/GaSb strained layer superlattice detectors (100% cut-off wavelength is 9.8 μm at 77 K). 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 1600 cm−1 exhibited superior performance with surface resistivity in excess of 104 Ω cm, dark current density of 2.7 × 10−3 A/cm2, and specific detectivity improved by a factor of 5 compared to unpassivated devices (VBias =  − 0.1 V, 77 K).

► 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.