Near-infrared photodetectors based on commercial InAs quantum dots

This is the authors' abstract. We don't add key points for this paper.

: The demand for low-power, self-powered, and solution-processed near-infrared (NIR) photodetectors, particularly those avoiding metals like Hg and Cd, and operating within the second biological window (NIR-II, 1000–1350 nm), is driving the development of alternatives to conventional epitaxial semiconductors. This work evaluates a solution-processed, self-powered NIR photodetector up to 1300 nm, employing commercially available, native ligand-preserved indium arsenide (InAs) quantum dots (QDs) integrated into a heterojunction architecture (ITO/ZnO/InAs/PTAA/Ag). Optimization of the sol-gel zinc oxide (ZnO) electron transport layer and poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) hole transport layer provides a favorable energy cascade for efficient, self-powered charge separation. Under zero external bias, the photodetector exhibits steady state responsivities of 10 -5 and 10 -3 A/W under 980 and 450 nm illumination, respectively. While idealized shot-noise approximations suggest higher theoretical upper bounds, full noise spectral density analysis reveals a low-frequency flicker (1 /f ) noise dominance and low external quantum efficiency (limited to a great extent by the low transmittance of the glass/ITO substrate) that restrict the actual experimentally measured specific detectivity (D*) to a modest range of 1.2×10 7 to 2.6×10 7 Jones between 900 and 1300 nm under 5 Hz modulation. The photodevices demonstrate rapid carrier dynamics with rise and fall times in the range of 1.2 and 1 μs under modulated 450 nm illumination at 62.5 kHz. These findings provide critical insights into the performance limits of non-toxic, native ligand-capped InAs QD photodetectors, highlighting key trade-offs in interface engineering and active layer optimization for future imaging applications.