Improved Broadband Photoresponse in Schottky‐Like Junction Using Carrier Selective NiO Contact on p‐Si

Abstract

A high performing broadband photodetector is designed using a NiO passivated rear contact. This paper demonstrates that the diode properties of an Al/p‐Si/ITO device can be improved by inserting an ultrathin sandwich NiO layer between Al/p‐Si. In addition, current‐voltage‐temperature characteristics reveal a significant enhancement of activation energy from 0.61 to 0.95 eV over the reference device. The effective barrier height is improved from 0.69 to 1.20 eV with the insertion of the NiO layer. Moreover, significant improvements in the responsivity and detectivity over a broadband wavelength from 300 to 1100 nm are verified. Comprehensive photodetection performance studies show a threefold reduction in the dark saturation current by inserting the ultrathin NiO layer, which creates zero bias photodetection with an impressive photoresponse ratio of more than 1500 and a responsivity of 1.52 A/W. The presented devices respond well even at an extremely low intensity 24 nW cm−2 of photodetection, suggesting the potential of the rear passivated contact for advanced photoelectric devices.