Infrared photodetectors based on graphene van der Waals heterostructures

TL;DR

This paper introduces graphene-based van der Waals heterostructure infrared photodetectors that leverage electron photoexcitation for high responsivity, gain, and potential high-speed IR detection, outperforming some existing IR detectors.

Contribution

It proposes a novel graphene van der Waals heterostructure photodetector model demonstrating enhanced photoelectric performance and high-speed IR detection capabilities.

Findings

High photoelectric gain and responsivity predicted

Potential for high-speed operation demonstrated

Comparable or superior to untraveled-carrier IR photodetectors

Abstract

We propose and evaluate the graphene layer (GL) infrared photodetectors (GLIPs) based on the van der Waals (vdW) heterostructures with the radiation absorbing GLs. The operation of the GLIPs is associated with the electron photoexcitation from the GL valence band to the continuum states above the inter-GL barriers (either via tunneling or direct transitions to the continuum states). Using the developed device model, we calculate the photodetector characteristics as functions of the GL-vdW heterostructure parameters. We show that due to a relatively large efficiency of the electron photoexcitation and low capture efficiency of the electrons propagating over the barriers in the inter-GL layers, GLIPs should exhibit the elevated photoelectric gain and detector responsivity as well as relatively high detectivity. The possibility of high-speed operation, high conductivity, transparency of the GLIP contact layers, and the sensitivity to normally incident IR radiation provides additional potential advantages in comparison with other IR photodetectors. In particular, the proposed GLIPs can compete with unitravelling-carrier photodetectors.