High Responsivity, Large-Area Graphene/MoS2 Flexible Photodetectors

TL;DR

This paper reports the development of flexible, large-area graphene/MoS2 photodetectors with high responsivity and stability, suitable for wearable visible-light sensing applications.

Contribution

It introduces a novel fabrication of high-responsivity, large-area, flexible photodetectors based on CVD-grown graphene and MoS2 stacked on PET substrates, with significantly improved performance.

Findings

External responsivity of 45.5A/W at 642nm

Photoconductive gain up to 4x10^5

Stable operation under bending with 6cm curvature

Abstract

We present flexible photodetectors (PDs) for visible wavelengths fabricated by stacking centimetre-scale chemical vapour deposited (CVD) single layer graphene (SLG) and single layer CVD MoS2, both wet transferred onto a flexible polyethylene terephthalate substrate. The operation mechanism relies on injection of photoexcited electrons from MoS2 to the SLG channel. The external responsivity is 45.5A/W and the internal 570A/W at 642nm. This is at least two orders of magnitude higher than bulk-semiconductor flexible membranes and other flexible PDs based on graphene and layered materials. The photoconductive gain is up to 4x10^5. The photocurrent is in the 0.1-100 uA range. The devices are semi-transparent, with just 8% absorption at 642nm and work stably upon bending to a curvature of 6cm. These capabilities and the low voltage operation (<1V) make them attractive for wearable applications.