Zero-Dimensional PbS Quantum Dot–InGaZnO Film Heterostructure for Short-Wave Infrared Flat-Panel Imager

Abstract

There is a growing demand for human-eye-invisible short-wave infrared (SWIR) detection due to its potential in applications in areas such as medical diagnostics, environmental monitoring, and night vision. PbS colloidal quantum dots (QDs) are a promising light absorber for SWIR detection. Herein, we report on a PbS QD/InGaZnO (IGZO) heterostructure-based phototransistor and flat-panel imager for human-eye-safe SWIR photodetection and high-resolution imaging. Such hybrid phototransistors show good electrical performance and obvious photoresponse behaviors with a maximum responsivity of 104 A/W and specific detectivity of 1012 Jones under 1310 nm SWIR illumination. We found that PbS QD ligand molecules significantly impact the environmental stability. Phototransistors featuring a tetrabutylammonium iodide (TBAI) ligand exhibit excellent air stability with no serious degradation after exposure to air for 3 weeks, while phototransistors with ethanedithiol (EDT) ligands lose their SWIR detecting capability within 2 weeks. Such an improved air stability may be correlated with the TBAI ligand passivation effect that is confirmed by X-ray photoemission spectroscopy analyses. PbS QDs are patterned on the flexible IGZO transistor array by photolithographic lift-off method for implementing a more practical imaging pixel array. Furthermore, we demonstrate a prototype of 1.3 μm SWIR flat-panel image sensor array, establishing its potential application in advanced developments as a gate-tunable, highly sensitive, high-resolution, and large area flat-panel SWIR imager.

Highly sensitive active pixel image sensor array driven by large-area bilayer MoS2 transistor circuitry

“…To obtain the colored image, each pixel of the image sensor array was measured with the turtle stencil under RGB light that differs from pixel to pixel, respectively. The light stencil projection method was inspired and developed from previous reports 30 , 64 . Lee et al 30 reported a single-pixel imager and the image scanning system with three different light sources (RGB).…”

A Review of Phototransistors Using Metal Oxide Semiconductors: Research Progress and Future Directions

“…Hwang et al reported a PbS‐QD/IGZO‐based hybrid phototransistor and a flat‐panel SWIR imager. [ 139 ] Figure 12j shows a schematic illustration view of the QD/IGZO phototransistor. In this study, two ligands, tetrabutylammonium iodide (TBAI) and ethanedithiol (EDT), which have been widely employed for PbS‐QD‐based devices, were selected.…”

Fabrication, material regulation, and healthcare applications of flexible photodetectors

“…58,89 IR image sensors can be used in night vision and biomedical diagnostics. 90,91 Visible light image sensors can be used in face recognition and electronic eyes. [92][93][94] UV image sensors can be used in remote sensing and skin condition monitoring.…”