Superhigh Gain InGaN/GaN Visible-Light Photodetector Using Polarization Heterointerface Barrier and Single-Carrier Superlattices

Visible-light detection with high sensitivity and strong wavelength selectivity is highly desired in emerging applications. Here, we demonstrate a high-performance visible-light photodetector with an active region composed of a polarization induced barrier and single-carrier superlattices (SCSLs). The barrier at SCSLs/GaN heterointerface brings both a low dark current and a high gain originating from the photoinduced barrier reduction effect. Meanwhile, the designed InGaN/GaN SCSLs allow the photoelectrons in the quantum wells to escape, but photogenerated holes are weakly localized, thus generating the additional photoconductive gain. The resulting devices exhibited a super-high gain of 7.8 x 104, a large detectivity of 1.2 x 1016 jones, and a relatively fast response speed with rise/falling time of 2.5/89.6 ns. Also, a 400/500-nm rejection ratio greater than 3 x 105 was shown at 1 V, indicating excellent wavelength selectivity.