The Polymer Society of Korea

Abstract

Colloidal quantum dots (CQDs) based on Pb-free III–V semiconductors have emerged as promising materials for short-wave infrared photodetectors (PDs), combining spectral tunability, low toxicity, and solution processability. However, achieving both low noise and high-speed operation, particularly beyond 1500 nm, remains challenging due to intrinsic material and device-level limitations. In this work, we introduce a novel device architecture that addresses these constraints through energy band engineering and optimized carrier transport. The resulting photodetector achieves a significantly reduced dark current density of 9.7×10⁻⁴ mA/cm² at –0.2V, over three orders of magnitude lower than conventional CQD-based PDs. Furthermore, the device exhibits a fast photoresponse time of 24ns and high operational stability under ambient conditions.