InAs/GaSb type-II superlattice materials have attracted in the field of infrared detection due to their high quality, uniformity and stability. The performance of InAs/GaSb type-II superlattice detector is limited by dark noise and light response. This work reports a gradual funnel photon trapping (GFPT) structure enabling the light trapping in the T2SL detector absorption area. The GFPT detector exhibits an efficient broadband responsivity enhancement of 30% and a darker current noise reduction of 3 times. It has excellent passivated by atomic layer deposition and achieves a high detectivity of 1.51 × 1011 cm Hz1/2 at 78 K.