Passivation studies of GaSb-based superlattice structures

• Ammonium sulfide treatment reduces native oxides on antimony-based surface.
• The sulfuration significantly improves the electrical properties of the detector.
• Sulfur-based treatment is a promising passivation method for infrared devices.

The effect of (NH4)2S-based chemical treatment on type-II InAs/GaSb superlattice has been investigated. X-ray photoelectron spectroscopy and spectroscopic ellipsometry together with the fractional derivative spectrum model have been used for surface and interface characterization. It has been shown that As2S3 and In2S3 compounds are created during 21% (NH4)2S-based chemical treatment. Additionally, the reduction of leakage current of InAs/GaSb-based photodetectors has been observed. These results indicate that 21% (NH4)2S chemical treatment seems to be a promising long term stable passivation method for InAs/GaSb superlattice-based photodetectors.