Highly responsive near-infrared photodetector with low dark current using graphene/germanium Schottky junction with Al2O3 interfacial layer

Abstract

The performance of a graphene/Ge Schottky junction near-infrared photodetector is significantly enhanced by inserting a thin Al2O3 interfacial layer between graphene and Ge. Dark current is reduced by two orders of magnitudes, and the specific detectivity is improved to 1.9 x 10(10) cm . Hz(1/2)W(-1). The responsivity is improved to 1.2 AW(-1) with an interfacial layer from 0.5 AW(-1) of the reference devices. The normalized photo-todark current ratio is improved to 4.3 x 10(7) W-1 at a wavelength of 1550 nm, which is 10-100 times higher than those of other Ge photodetectors.