Reduction of surface leakage current in InAs/GaSb strained layer long wavelength superlattice detectors using SU-8 passivation

We report on SU-8 passivation for reducing surface leakage current in type-II InAs/GaSb strained layer superlattice detectors (lambda(100% cut-off) similar to 12 mu m). The electrical behavior of SU-8 passivated and unpassivated devices was compared for devices with variable mesa sizes. Dark current was reduced by more than one order of magnitude for the small area (50 mu m x 50 mu m) passivated diode at 77 K. The surface resistivity, the responsivity and specific detectivity were measured for SU-8 passivated devices and are equal to 204 Omega cm, 0.58 A/W and 3.49 x 10(9) Jones, respectively (77 K). (C) 2010 American Institute of Physics. [doi:10.1063/1.3499290]