High responsivity Si-based near-infrared photodetector with surface microstructure

To apply Si-based photodetectors in the near-infrared band their responsivity needs improvement. A regular and orderly microstructure array was formed on the surface of silicon-based photodetectors by plasma lithography. Besides, an Al2O3 film was grown on the microstructure surface by atomic layer deposition (ALD) to study its anti-reflection and passivation effects. The surface reflectivity and I - V characteristic curves of the device were compared and the light responsivity of the device under 808 nrn near-infrared light was calculated. It is found that the responsivity of the device is increased from 0. 063 A/W to 0. 83 A/W.