Hybrid quantum dot-tin disulfide field-effect transistors with improved photocurrent and spectral responsivity

TL;DR

This paper demonstrates that doping tin disulfide FETs with quantum dots significantly enhances their photocurrent and spectral responsivity, mainly through energy transfer mechanisms, leading to improved optoelectronic performance.

Contribution

The study introduces a hybrid QD-SnS2 FET device with substantially improved photosensitivity and spectral responsivity, revealing the role of energy transfer and charge mobility enhancement.

Findings

Photocurrent response increased by over 500%

Spectral responsivity exceeded 650 A/W at 400 nm

Enhanced charge mobility due to reduced Schottky barrier

Abstract

We report an improved photosensitivity in few-layer tin disulfide (SnS2) field-effect transistors (FETs) following doping with CdSe/ZnS core/shell quantum dots (QDs). The hybrid QD-SnS2 FET devices achieve more than 500 percent increase in the photocurrent response compared with the starting SnS2-only FET device and a spectral responsivity reaching over 650 A/W at 400 nm wavelength. The negligible electrical conductance in a control QD-only FET device suggests that energy transfer between QDs and SnS2 is the main mechanism responsible for the sensitization effect, which is consistent with the strong spectral overlap between QD photoluminescence and SnS2 optical absorption as well as the large nominal donor-acceptor interspacing between QD core and SnS2. We also find an enhanced charge carrier mobility in hybrid QD-SnS2 FETs which we attribute to a reduced contact Schottky barrier width due to an elevated background charge carrier density.