Enhancing the device performance of SiNP array/PtTe2 heterojunction photodetector by the light trapping effect

In this study, we have demonstrated the fabrication of a highly sensitive photodetector, which was based on Si nano-pillar (SiNP) array/PtTe2 heterojunction that can work under a self-powered mode of operation. The as-fabricated heterojunction exhibits the obvious current rectifying behavior with a rectification ratio of 6 x 10(3) at a bias voltage of +1 V. Moreover, it displayed an intriguing photoelectric ability to a wide range of illumination from ultraviolet to near-infrared light. Under light illumination at 980 nm, the photodetector exhibits a responsivity of 0.71 A W-1, a specific detectivity of 2.81 x 10(11) Jones, and an external quantum efficiency of 89.9 %, respectively. More importantly, the device has a fast response speed of tau(raise)/tau(fall) of 6.21/26.3 mu s. Thanks to the light trapping effect of the surficial nanostructure, the SiNP array effectively improves the absorption of the heterojunction, and therefore enhances the detecting performance of the device. Moreover, the device is able to record a near-infrared letter with acceptable resolution. All of these results suggest that present two-dimensional material may have potential application in future high-performance optoelectronic devices. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study demonstrates the fabrication of a highly sensitive photodetector based on Si nano-pillar/PtTe2 heterojunction, which exhibits remarkable photoelectric abilities across a wide range of illumination. The device shows impressive responsivity, detectivity, and external quantum efficiency, with a fast response speed. The results suggest potential applications for future high-performance optoelectronic devices using two-dimensional materials.