Photocapacitance study of GaSb: In, As for defect analysis in InAs/GaSb type-II strained layer superlattices

•GaSb doped with In and As and InAs/GaSb type-II superlattice was grown and fabricated into devices.•Steady-state photocapacitance measurements were used to identify defect levels in these devices.•A defect level was observed in the GaSb samples, that was not effected by the In or As content.•A defect level was also seen near midgap for the superlattice sample.

Steady-state photocapacitance measurements were used to characterize GaSb incorporated with In, As, and a control sample. Evidence of a trap level at 0.55 eV was observed for all samples. The change in the capacitance for the sample with indium was about half the change for the other samples, indicating that the addition of indium modified the near-mid-gap trap levels. Another change in capacitance starting at 0.71 eV was attributed to electrons from the valence band filling levels close to the conduction band.