Ultra-low Noise Level Infrared Quantum Dot Photodiodes with Self-Screenable Polymeric Optical Window.

Quantum dot photodiodes (QPDs) have garnered significant attention because of their unparalleled near-infrared (NIR) detection capabilities, primarily attributable to their size-dependent bandgap tunability. Nevertheless, the broadband absorption spectrum of QPD engenders substantial noise floor within superfluous visible light regions, notably hindering their use in several emerging applications necessitating the detection of faint micro-light signals. To overcome these hurdles, we demonstrated a self-screenable NIR QPD featuring an internal optical filter with a thick polymeric interlayer to reduce electronic noise. This effectively screened out undesirable visible light regions while reducing the ionized defect owing to decreased density of state (DOS), yielding an extremely low dark current (∼10 10 A/cm 2 at V = -1 V). Consequently, the electronic noise spectral density was attained at levels below 10 -27 ∼ 10 -28 A 2 /Hz, and responsivity (R) dropped to 92% within the visible light spectrum. This article is protected by copyright. All rights reserved.