Improving of Sensitivity of PbS Quantum Dot Based SWIR Photodetector Using P3HT.

Kyeong-Ho Seo,Jaewon Jang,Jin-Hyuk Bae,In Man Kang

doi:10.3390/ma14061488

Abstract

In this study, we improved the photosensitivity of the lead sulfide quantum dot (PbS QD)-based shortwave infrared (SWIR: 1.0–2.5 μm) photodetector by blending poly(3-hexylthiophene-2,5-diyl) (P3HT) with PbS QD. The PbS QD used for SWIR photoactive layer showed an absorption peak at 1410 nm. In addition, by using zinc oxide nanoparticles (ZnO NPs) as an interlayer, we obtained the stable current characteristics of our device. To confirm the effectiveness of P3HT on the PbS QD-based SWIR photodetector, we compared the electrical characteristics of a PbS QD-based device with a hybrid P3HT:PbS QD-based device. In the reverse bias region, the current on/off ratio of the PbS QD-based device was 1.3, whereas the on/off ratio of the hybrid P3HT:PbS QD-based device was 2.9; 2.2 times higher than the PbS QD-based device. At −1 V, the on/off ratio of the PbS QD-based device was 1.3 and the on/off ratio of the hybrid P3HT:PbS QD-based device was 3.4; 2.6 times higher than the PbS QD-based device. The fabricated P3HT:PbS QD-based device had the highest on/off ratio when −1 V voltage was applied.

Highlights

Shortwave infrared (SWIR: 1.0–2.5 μm) photodetectors are widely used in various fields such as telecom, temperature measurement, remote sensing, and spectroscopy [1,2,3,4]
PbS QDs have the advantages of having high stability in air, size tunability, and flexible substrate compatibility [8,9,10,11], so this material emerges as a promising candidate for SWIR detection
This study focused on the photosensitivity improvement of the PbS QD-based SWIR photodetector with or without P3HT

Summary

Introduction

Compound semiconductors, such as InGaAs, InAs, are applied to the fabrication of SWIR photodetectors. These materials require molecular beam epitaxial process to grow which have the high fabrication cost and difficulty of large-scale production [5,6]. To overcome these difficulties, many researchers have paid attention to lead sulfide quantum dots (PbS QDs), another SWIR active material, due to cost-effectiveness and large-scale manufacturability [7]. The ITO/PbS QD/Al structure is reported to have poor performance due to bad rectification characteristics [14,15]

Methods

Findings

Discussion

Conclusion