Hybrid graphene-quantum dot phototransistors with ultrahigh gain

TL;DR

This paper presents a hybrid graphene-quantum dot phototransistor with ultrahigh gain and spectral tunability, significantly outperforming pure graphene detectors in sensitivity and responsivity.

Contribution

The study introduces the first graphene-based phototransistor leveraging quantum dots for enhanced light absorption and gain, achieving ultrahigh responsivity and spectral selectivity.

Findings

Ultrahigh gain of 10^8 demonstrated

Responsivity exceeds that of pristine graphene by ten orders of magnitude

Device exhibits gate-tunable spectral sensitivity from visible to shortwave infrared

Abstract

Graphene has emerged as a novel platform for opto-electronic applications and photodetector, but the inefficient conversion from light to current has so far been an important roadblock. The main challenge has been to increase the light absorption efficiency and to provide a gain mechanism where multiple charge carriers are created from one incident photon. Here, we take advantage of the strong light absorption in quantum dots and the two-dimensionality and high mobility of graphene to merge these materials into a hybrid system for photodetection with extremely high sensitivity. Exploiting charge transfer between the two materials, we realize for the first time, graphene-based phototransistors that show ultrahigh gain of 10^8 and ten orders of magnitude larger responsivity compared to pristine graphene photodetectors. These hybrid graphene-quantum dot phototransistors exhibit gate-tunable sensitivity, spectral selectivity from the shortwave infrared to the visible, and can be integrated with current circuit technologies.