Gassenq, Alban

Hens, Zeger

Hu, Chen

Justo Zarraquiños, Yolanda

Roelkens, Günther

English

Ghent University Academic Bibliography

Colloidal Quantum Dot Photodetectors on Silicon for Short-wave Infrared applications Chen Hu1,2,3,* , Alban Gassenq1,2 , Yolanda Justo3, Zeger Hens3 , Gunther Roelkens1,2  1 Photonics Research Group, INTEC Department, Ghent University-IMEC, Sint-Pietersnieuwstraat 41, 9000 Ghent, Belgium 2 Center for Nano- and Biophotonics (NB-Photonics), Ghent University, Belgium 3Physics and Chemistry of Nanostructures, Ghent University, Krijgslaan 281-S3, 9000 Gent, Belgium  Abstract: The interest in short-wave infrared (SWIR) photodetectors has grown considerably for spectroscopic sensing applications. Many molecules that we want to monitor in our environment have bands of absorption lines in this wavelength range. Traditional high-sensitivity photodetectors used in spectroscopic systems are discrete components based on, e.g, quantum-confined epitaxial materials. As optoelectronic materials, solution processed colloidal quantum dots (QDs) or nanocrystals (NCs) offer an alternative way to realize this functionality, providing a path to low-cost high-detectivity SWIR detectors. In this study, PbS colloidal quantum dots are explored for SWIR photodetectors. Starting from colloidal QDs with their as-synthesized organic ligands, uniform, ultra-smooth and crack-free QD films are grown using layer-by-layer approach. Here, each cycle involves the deposition of a QD layer by dipcoating, the replacement of the native organic ligands by inorganic moieties, such as OH- and S2-, followed by a thorough cleaning of the resulting film. These short inorganic ligands are used to facilitate the charge carrier transport. PbS-based quantum dot photoconductors were fabricated on interdigitated gold electrodes. For PbS-based detectors with a cut-off wavelength of 2.2μm, a responsivity of 200A/W is measured at 1.5μm, reflecting the large internal photoconductive gain of the devices. The integration of these detectors on silicon photonic circuits will be discussed.  Key words: colloidal quantum dots, solid-state ligand exchange, photodetectors                                                           * Corresponding author: chenhu@intec.ugent.be; gunther.roelkens@intec.ugent.be 

Colloidal quantum dot photodetectors for short-wave infrared applications

https://biblio.ugent.be/publication/3201977/file/4292329

Colloidal quantum dot photodetectors for short-wave infrared applications

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Ghent University Academic Bibliography